1.  Introduction

The Society of Tribologists and Lubrication Engineers (STLE), is one of the largest professional societies in the field of tribology and lubrication engineering, which serves more than 15,000 industry professionals worldwide. STLE is a non-profit technical society whose members encompass the academic, government and business community.

STLE’s mission is to advance the science of tribology and the practice of lubrication engineering in order to foster innovation, improve the performance of equipment and products, conserve resources and protect the environment.

STLE has published two previous reports (2014 and 2017) on trends and issues for their members and the tribology and lubrication engineering community. STLE will soon be releasing the 2020 Report on Emerging Issues and Trends in Tribology and Lubrication Engineering. These reports represent the outcome of extensive multi-phase research efforts. These reports, and the research effort behind them, encompass the global opinions and experiences of nearly 1,000 tribologists and lubrication engineers who participated in the research as advisors and editors.

This presentation will highlight some of the most important trends and issues found in the 2020 Report on Emerging Issues and Trends in Tribology and Lubrication Engineering.

It is our hope that this presentation will provide a forward-looking snapshot of the future of tribology and lubrication engineering to those attending the conference.

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The International Council for Machinery Lubrication recently published the overarching standard ICML 55 on the management of lubricated mechanical assets.  This seminal standard is the work-product of four years by 45 experts who possess broad knowledge on subjects both central and peripheral to the lubrication field. These include 34 trainers and consultants, nine book authors, 40 separate organizations and 15 countries.  In other words it is the completed product of the global lubrication, tribology, reliability, condition monitoring and asset management community. Further, this standard is mapped structurally to the more holistic asset management standard  ISO 55001.

Most of the experts who created this standard also participated in the formation of the new professional certification Machinery Lubrication Engineer (MLE).  It is of no coincidence that the ICML 55 and the MLE were launched at nearly the same time.  This is because the Body of Knowledge that a candidate must master to become a certified MLE is perfectly and intentionally aligned to each of the asset management subjects delineated in ICML 55.1. 

Any organization on an ICML 55 journey requires an individual with both technical and programmatic knowledge to blaze the trail in pursuit of full organizational certification. The MLE is that individual.  This perfect alignment is strategic and purposeful, engineered to facilitate achievement and sustainability of lubrication in the context of reliability, maintenance and asset management, as well as ICML 55.1 certification.

My paper will introduce the ICML 55 and described the critical role of the MLE towards programmatic asset management certification.

More and more attention goes to carbon neutrality.  The public's awareness has grown and the new European Green Deal reflects the ambition of Europe to become the first climate neutral continent by 2050.  But between the ambition of politicians with support of the public on the one hand, and actually reaching those targets on the other hand, stand both societal and technical challenges.

One opportunity to reduce the climate impact of products, is to reduce the carbon footprint in every stage of production, transport, lifetime and recycling.  Good LCA is key to this.  Another opportunity is to extend the lifetime of the product so that less 'circles' of production-transport-lifetime-recycling need to be followed.  In short, by extending the lifetime of products, the carbon footprint can easily be reduced.  This relates to the wear resistance of components and is thus a very basic tribological challenge : how to make parts more wear resistant ?  Material selection, design and lubrication play interacting roles in extending the lifetime of components.

There is a lack of data, related to wear resistance of new materials and lubricants, though.  Searching databases and literature, no reliable and comparable data can be found to base a material selection upon.  This initiative proposes a change of paradigm : instead of considering a tribological test as a single result research objective, we propose to productionize wear data, offering affordable information to product developers and lubricant formulators.  The way to reach this objective is through productionizing the test infrastructure, the test methodology, measurement techniques and data treatment.  The FACT material selection project , which received an EU Certificate of Excellence, will be presented as a way towards higher efficiency in supporting the European and Global climate goals.

Abstract

High-Strength Low-Alloy (HSLA) steels are the most employed structural materials in offshore applications due to their high mechanical properties, but they are very susceptible to corrosion in seawater [1], which can reduce their durability under combined corrosion-wear working conditions (tribocorrosion). The former investigations on tribocorrosion of HSLA steels employed in offshore applications [3,4], evinced the high degradation of the steels in such demanding working conditions, showing an acceleration of corrosion during wear experiments, as consequence of the synergism generated between wear and corrosion. The material loss was considerably higher in tribocorrosion conditions compared to sole corrosion tests in seawater. Furthermore, several parameters such as seawater temperature or salinity have also been studied and confirmed to influence the degradation of the steels.

On the other hand, coatings have been widely employed to avoid or minimize corrosion of steel components and structures. Protective systems are also subjected to tribocorrosion conditions [5], but they are mainly selected by their ability to protect steel from corrosion. Once the coatings are damaged, their performance can be compromised, reducing their durability. In the second part of this work, investigations have been carried out in the tribocorrosion performance of coatings currently employed in the protection of mooring lines of floating structures [6,7]. These studies revealed that the corrosion behavior of the coatings was affected by wear.

References

1. P. Ault. Journal of Protective Coatings and linings 23 (2006) 42-47
2. W. Momber, et al. Journal of Coatings Technology and Research 15 (2018) 13-40
3. A. López, et al. Wear 338-339 (2015) 1-10
4. A. López-Ortega, et al. Tribology International 121 (2018) 341-352
5. R.J.K. Wood. Journal of Physics D: Applied Physics 40 (2007) 5502-5521
6. A. López-Ortega, et al. Surface & Coatings Technology 349 (2018) 1083-1097
7. A. López-Ortega, et al. Corrosion Science 143 (2018) 258-280

Rolling element bearings are undergone unfavourable work conditions in wind turbine gearboxes. Thus, they suffer a premature failure mode, which is driven by "White etching crack" (WEC) and it entails a reduction of a 1-20 % of the bearing’s life, hence the wind turbine lifetime is reduced from the estimated 20 years to less than 2 years. The "White structure flacking" (WSF) is due to WEC formation at 1 mm beneath the contact surface, where the shear stress is the highest. WEC failure consists of networks of microcrack connected with microstructural alterations, called “White Etching Area” (WEA).

Hydrogen, transient conditions, electrical current and non-metallic inclusions are suggested as drivers of WEC. Hydrogen seems to have the most determining role on WEC formation, but it is not fully understood where hydrogen comes from.

Besides, the study presents the main experimental procedures used to reproduce WEC. Two test methods conducted by well-regarded researchers are the FE8 test and the 2Disc test. In FE8 test two cylindrical thrust roller bearings are fitted into a shaft and an axial load is applied by a plate spring package or by using a hydraulic cylinder. The rolling bearings are lubricated at a certain flow rate and temperature. The “2Disc” test consists of two rollers which are fitted into two separate shafts driven by different motors, which allows setting a specific Slide-to-Roll Ratio (SRR). The rollers are brought into contact under a normal load. Different lubrication systems can be used: bath lubrication and spall lubrication. Commonly friction coefficient, tangential load and contact temperature can be registered.

In this work, results from several studies are collected with the aim of giving a broad insight about this premature failure. The results obtained from testing hydrogen pre-charged rollers on the "Twin disc" test bench under demanding operating conditions are discussed.

Toroidal type Continuously Variable Transmissions (T-CVTs) are mechanical systems that can change the transmission ratio continuously between two limits. This characteristic enables working always in the most efficient point of a mechanical system, which is an important issue nowadays. The power transference is carried out by means of traction forces between two coaxial discs pressed against several rollers, which differentiates this transmission type from conventional geared devices.

The literature review shows that a small amount of slip is essential to increase the traction coefficient, but contrary to geared systems, in this transmission type, the sliding speed does not only depend on geometrical parameters of the components. The contact pressure, ellipticity ratio of the interface and kinematics of the transmission such as spin, plays an important role in the traction coefficient and the sliding speed; consequently, the performance, efficiency and fatigue life of the mechanism is affected.

The current work presents a contact efficiency model for Toroidal CVTs. In this transmission, non-conformal lubricated elliptical contact points make the power transmission. The traction calculation has been carried out by numerical integration on the contact ellipse where the pressure is assumed to be Hertzian and the kinematic behaviour of each cell is analytically computed from the geometry and operating conditions. Meanwhile, the traction coefficient is considered a constant value measured in a ball on disc tribometer for different values of contact pressure, entrainment speed, sliding speed and temperature. The influence of geometry has been analysed, focusing on the influence of the toroidal cavity radius and the conformity ratio of disc and rollers, in contact pressures and kinematics of the mechanism. Results show that the geometry have a direct effect on the tribological behaviour of this transmission type, and thus on the traction capacity.

Tribochemically active lubricants are essential to form the tribofilms that enable safe and reliable operations of high performance moving mechanical assemblies (MMA). Triboimproving lubricant additives (FM/AW/EP) have been empirically developed over the last century, resulting in a wide range of additives. These additives provide conventional base oils with the necessary tribochemical activity that enable effective lubrication of high performance machinery used all over the world. Unfortunately, there are many applications where operational conditions preclude the use of these conventional base oils, such as in space applications. This work evaluates the feasibility of a vacuum compatible multifunctional ionic liquid lubricant, for use with multiply alkylated cyclopentane base oil (MAC). Actuator gearboxes are operated under starved conditions in nitrogen atmosphere to evaluate the effectiveness of the tribofilm forming lubricant (designated P-SiSO). The effectiveness of P-SiSO was evaluated from macro to micro scale in both surface and sub-surface analysis by use of microscopy (optical, interferometric, SEM) and X-ray microtomography (XMT), and mechanisms of effective lubrication are discussed.

In lubricant development, foam generation must be avoided. Foam worsens the efficiency of lubricants in its both main functions: as fluids for cooling and greasing. To stop foam formation, so called “antifoamers” are commonly used.

In this presentation, we show how the effectiveness of antifoamers in industrially used lubricants can be quickly and easily measured in situ by using the KRÜSS Dynamic Foam Analyzer - DFA100. Foam height during formation and decay are controlled by the transmission of light through the foam. This allows the screening for the best antifoamer and its optimum concentration. We demonstrate the differences in foam volume and stability of oil-free cooling lubricants with and without additional antifoamer. We further compare the results to the foaming properties of a typical cleaning agent.

While lubricants are used for certain process steps, they are often unwanted in the final product and must be washed off in a washing step. It is important to optimize the cleaning time in order to achieve maximum efficiency. Contact angle measurements are a non-destructive method to determine the optimum cleaning time within only a few seconds. By using defined liquids, furthermore the surface free energy of the solids can be determined.

We use contaminated metal plates and clean them in an ultrasonic bath for defined times. Contact angles are measured and an evolution in values for the surface free energy is observed with increased cleaning times. A clean surface is symbolized by stable values. Measurements are performed with the KRÜSS Mobile Surface Analyzer ? MSA, whose mobility allows it to be used at-line.

ICML 55 is a new industry guideline following ISO’s 55000 Asset Management Standard. The guideline is a highly tactical, lubrication-specific standard designed to help end-users establish, implement, maintain and improve consistent lubricant management systems. Chapter 11 of this document focuses on Oil Reclamation and System Decontamination. This presentation will review the technologies and processes recommended in this document to ensure your organization is taking advantage of the latest advancements in oil reclamation and system decontamination.

Oil degradation products are well-known to form varnish and cause reliability concerns. Another impact of oil degradation products is their reactive-nature which causes accelerated antioxidant reactions and faster fluid degradation. This paper will summarize both laboratory simulations and field cases demonstrating how the use of a customized media can not only mitigate long-term deposit concerns, but will also extend antioxidant life, having a direct impact on the life of the lubricant

Lubricants used in rotating equipment degrade due to thermal stresses forming deposits commonly referred to as varnish. The impact on reliability is the escalation of bearing temperatures, often to a point which risks safe operation and can force an unplanned outage. This paper reviews the principles behind these temperature excursions and potential disruptions in the hydrodynamic film. It also presents case studies illustrating solutions to bearing temperature excursions, which in some cases can be solved in a matter of hours.

The low temperature pumpability of engine oils has been a concern of OEMs and blenders for decades. If an engine starts it is essential that oil flows quickly throughout the engine providing essential lubrication to all moving parts. High oil viscosity during low temperature starts could delay oil from pumping throughout the engine. In order to predict oil viscosity at cold temperatures, OEM and industry specifications have included bench tests to measure cold temperature pumpability, most typically the pour point and the MRV TP -1 viscosity tests. Several published studies from the 1990s clearly demonstrate the value of the MRV TP-1 test for predicting pumpability. Does this hold true for modern engines? Data and videos will be presented comparing cam shaft oiling times in a modern engine for oils of differing pour point and MRV viscosity, demonstrating the value low viscosity oils provide to cold start pumpability.

Wear debris generated during the service life of orthopaedic implants has been widely recognised as one of the critical factors which can influence the performance of those implants. It is thus of significant value to identify and predict when, where and how those debris are generated and to characterise them, particularly when new materials are being introduced into a specific clinical application. In this study, a preliminary experiment was carried out to investigate wear occurring at the plate and screw interface during screw insertion using novel Carbon Fiber Reinforced Polyether Ether Ketone (CFRPEEK) fracture fixation plates and screws made from titanium alloy (Ti6Al4V) in comparison with a commercial Titanium (Ti) plate. Based on the results, there was a limited amount of wear loss on the CFRPEEK plate (0.006 – 0.011 wt%). A combination of adhesive and abrasive wear was shown to be the dominant wear mechanism for the CFRPEEK plates studied, while total weight change was found to have increased on the Ti plate due to oxidation and material transfer from the screws to the plate. In comparison to Ti plates, CFR-PEEK could be a promising material for fracture fixation based on limited wear loss during screw insertion and removal.

Powertrain systems in vehicles are composed of a large number of moving mechanical assemblies (MMAs) and materials. The total efficiency of the component is determined by each MMA, which is designed to operate under medium-load and high-velocity conditions. Currently, cast iron, aluminium, and coatings on them are the major materials that are being used. A Lab-to-Field up-scaling tool will be applied to new materials for the prediction of the component energy efficiency. The challenge is to predict the energy efficiency (friction regime) of materials using AI-methods. In more details, multi-scale tribological simulations will be performed to elaborate the dominating friction laws. The simulation results will be compared to the expected performance in engines to verify if these friction laws are indeed dominant. Based on the friction laws established, AI-methodologies will be considered for benchmark correlations and eventually validated via engine tests.

In particular, the computational strategy followed here will aim at the numerical estimation of the friction coefficient on the micro-scale passing through all length scales below, i.e., from ab-initio calculations, e.g., on additives in the lubricant, molecular dynamics simulation for revealing the ordering of molecules in the lubricant and fluid dynamics to determine the roughness-dependent flow factors. Since this numerical framework is planned to be used for various textures, e.g., either computer-generated or experimental ones, the results are expected to be transferable to larger, say component length scales, by applying proper machine learning (ML) techniques.

In addition to engine tests, experimental data will be also obtained by using pin-on-disc-type as well as properly adapted SRV tribometers for closely following the contact situation of the engine components of interest. The surface topography will be measured before and after each test to use these surface data as input for various numerical simulations.

Capacitance based systems have been used for many decades to measure the thickness of lubricating films beneath the piston-rings of internal combustion (ic) engines. They have been used in investigations in bench-based test equipment and in engines in both motored and firing conditions. More recently, in addition to simply measuring lubricating film thickness, capacitance transducers have also been successfully employed to measure, or deduce, other parameters. These include:

• using the change in permittivity of the intervening medium between the ring and the cylinder to establish the positions of the inlet and outlet boundaries to a ring to determine the extent of the lubricating film,
• observing film thickness over successive strokes to establish the progressive transport of lubricant in the axial and circumferential directions,
• combining capacitance transducers with inductance transducers to measure the thickness of unconfined films on surfaces.

This paper begins by briefly reviewing the use of the capacitance technique for the investigation of lubricating film thickness in ic engine ring packs. It then describes the general operating principles of capacitance based lubricant film thickness measurement systems. Finally, the technical capabilities of “state-of-the-art” devices of this type are summarized and a range of measurements made in both test apparatus as well as motored and firing engines are presented to illustrate the scope of their applicability and practical value.

Specific fluids for electric and hybrid vehicles

It is irrefutable that vehicle electrification will create new classes of fluids and/or lubricants. The drivetrains and power electronics in electric vehicles (EV) and battery hybrid electric vehicles (BHEV) require cooling and have direct or indirect contact with fluids. Electrical and thermal properties are associated together and differ from those of traditional fluids and lubricant properties. During these contacts, the number of metallurgical different materials increases. The pre-existing lab tests for compatibility of fluids not include these materials. Finally, thermal management fluids will appear.

For indirect cooling, apart of water, polyglycols (PAGs) offer the highest heat capacity and thermal conductivity and in consequence the best heat transfer and transport. Enhancements by nano-particles slightly increase the thermal conductivity and decrease the heat capacity slightly, but more important is the enhancement of the heat transfer coefficient [W/(m²K)] through enhancing the convection. Stable dispersion over temperature and shear rate as well as time are challenging.

For direct, immersion cooling, anhydrous and insulating fluids are favored, like hydrofluoroethers and esters. Global Warming Potential (GWP) of a fluorinated ethers hast to be carefully regarded.

Friction reduction of tribosystems is another area of focus and correlates directly to the torque properties of EVs and transduces into range extension. Hydrolubes, are first low or ultra-low viscosity lubes, and may be considered as monofluids for thermal management and lubricants for gears. Arcing or electrosparks represent another nuissance for tribosystems in BHEVs and EVs. They can be overcomed by either insulating materials or electrically conductive lubricants and/or those forming electrically conductive tribofilms.

In contrast to conventional “equilibrium” chemical reactions, the reaction path of tribochemical processes depend not only on the chemical structure of the solids, lubricants and the environment, but also on how mechanical energy is supplied and dissipated.

The volatile and gaseous products of tribochemical reactions, which come into being at a buried interface and are being emitted into the environment, carry valuable information on the hidden processes, which control the durability and performance of a lubricant. This information is delivered in situ and in real time giving an insight into complex tribochemical processes. Significant advancement in characterization of gas triboemission was recently achieved due to combination of three elements: mass-spectrometer, nearly zero-emission tribological cell and a dynamic gas expansion system. An original method of data analysis was also developed. This method was emploied for the analysis of tribochemical processes in ionic liquid lubricants. It was found that tribochemical processes are much more complex than it was deduced from the post mortem characterization of contact surfaces. For instance, it was demonstrated that both cationic and anionic moieties of ionic liquids can react not only with the substrate, but also with each other. Structural and chemical degradation of diamond-like carbon coatings was analysed by characterization of methane, hydrogen, argon and higher alkane emission. Disturbance of low friction was associated with increasing methane/hydrogen ratio, while structural damage was sensed by Ar emission. Finally, analysis of gas triboemission revealed unusual tribochemical pathways in promising solid lubricant systems based on C-MeS2 nanostructures.

Greases used for rolling bearings lubrication are subjected to high thermal and mechanical effects that can lead to the loss of grease lubricating properties. It causes wear, serious materiel damage and safety hazards for users. The aim of this work is to develop an empirical model of grease aging based on chemical and mechanical degradations. A series of experiments on fresh greases was first conducted in order to reproduce their real aging conditions. The impact of mechanical degradation was studied by the shearing action of a grease worker (155 to 180 rpm at 105 °C, NF ISO 2137). The chemical degradation by oxidation was evaluated on air at 130 °C.

The chemical structure of the grease is clearly modified by oxidation as seen by IR spectroscopy (Fig. 1). From 200 to 1250h of oxidation, in comparison with fresh grease, several new bands for example located between 1780 and 1700 cm-1 appear corresponding to new carbonyl species (aldehydes or ketones). In addition, the thickening carboxyl bands located at 1580 and 1560 cm-1 disappear after an oxidation time of 500h. [4].

Grease oxidation and shearing affect its ability to lubricate (Fig. 2) as seen in rheology with the drastic flow point decrease from 24hof shearing from 1328 to 238 Pa.s.These degradations are confirmed by Scanning Electron Microscopy (SEM) (Fig. 3) for the thickener separated from the oil. The grease thickener is a matrix of fibers characterized by a large surface area. Oil is held into the holes formed in the matrix. Long twisted fibers are observed for fresh thickener. But oxidized fibers soften and tend to aggregate and sheared fibers are broken. The degradations by oxidation and shearing impact the thickener/oil chemical interactions, the morphology and the mechanical stability of greases that cause the oil bleeding.

Ability of lubricants to protect the moving parts can be severely affected due to ageing. This is attributed to depletion of additives (Ex. AW, EP and VII’s), increase in oxidation and contaminants like water, particulate matters, in aged lubricants. Although the ageing of lubricants is an issue, there are no proven lab scale test methods that can be used for investigation. In this study, we have proposed a lab scale test bed that can simulate ageing of transmission oils, that can also measure its tribological and chemical properties. Shear stability tester (or KRL) with a tapered roller bearing is used to breakdown the polymers in the lubricants. In this case the ageing is determined by the loss in viscosity, that can be compared with transmission process in the field conditions. Lubricants such as Shell spirax 80W90, Castrol axle 80W90 and RL 209 (control) were KRL aged for 100 h.  Shell spirax showed signs of severe ageing due to higher viscosity loss compared to Castrol and control. This was confirmed in our thermal ageing tests at 120oC for 120 h in an oven. Aged lubricant, as obtained from the KRL or oven was investigated for depletion of friction modifiers and antiwear additives using the four-ball tester (or FBT-3) and high frequency reciprocating rig (HFRR). KRL aged Shell spirax showed higher wear compared to Castrol, indicating relatively higher depletion of antiwear additives. Similar observation was made for thermally aged Shell spirax compared to Castrol. The temperature stability and molecular weight of aged lubricants were investigated using thermogravimetric analysis (TGA) and gel permeation chromatography (GPC).

In the industry there is a need to monitor physical variables that indicate the condition of
rotative machines, reducing the probability of an unexpected failure that cause human,
material, economic and reputational losses for the company.
The large amounts of information obtained in industrial maintenance require technological
tools as wireless communication (Wi-care), cloud databases (I-See), condition lubrication
(Lube-care), virtual applications and artificial intelligence algorithms to obtain results that
help the maintenance department taking decision based on data.
According to the practical cases developed in the company, it has been shown that the
needs of predictive maintenance vary according to the methods used to obtain the
information of the machines and how the industrial companies are prepared to lead the
change through digitalization of information which is forcing the service companies to be
more agile and customize each solution for each project.
This work presents a strategy to face the change towards Industry 4.0 in maintenance
management, presenting some results obtained in the implementation of online condition
monitoring of rotative machines, lubrication based on condition, KPI’s dashboard
visualization, and others solutions.
Key words: Industry 4.0, Condition Based Maintenance (CBM), Predictive maintenance,
IIOT, maintenance big data

Some form of AI (Artificial Intelligence) has been applied to Fa (Fluid Analysis/Oil Analysis) and other CM (condition monitoring) services for decades (ca 1979), however, there has not been much activity toward looking at Fa more deeply, as Intelligent Agents are not yet widely utilized. Further there have been near-zero evaluation methods for composite CM aspects outside of Fa, so that additional data, such as from Vibration or Ultrasound or Thermography can be brought into the evaluation effort, tempering  or embellishing the comment that will ultimately be made. This disparity prevents the synergy that is, or could be, inherent in viewing all CM data toward a best possible evaluation.

The author will present the notion of a fully automated, deep-dive intelligent agent for Fa, then show some examples toward adapting composite CM data into an amalgamated data assessment and evaluation for a fully comprehensive/holistic approach.

You cannot implement the best maintenance strategies for all assets, at all times? Do you waste money with ineffective strategies?

Asset Strategy Management (ASM) could be what your organization needs.

ASM means that:

1. The best strategies, developed by the best experts in the field, are in place;
2. They are implemented in all your assets all the time;
3. They continually evolve based on real data and an effective review process.

Unlock the value that is currently lost through ineffective strategies and the inability to implement the best tactics for all assets, at all times.

What is the ASM?

Most organizations have attempted to standardize master data and even strategies for common equipment.

However, there are two common problems that stop organizations:

1. 1. The implementation of generic content cannot be performed effectively within a CMMS / ERP system. These systems are designed to support work execution; No strategic decision management. Essentially, they cannot truly use the generic content in a continuous and connectable way.
2. 2. While there may be a defined work management process to boost the execution of the work, there is a limited or no process to manage the review and evolution of the strategies and their content. Simply put, the parameters associated with the strategies can be changed on a whim without the need for approval by experts in the field.

Essentially, most organizations have not separated work management and strategy management; they are completely different processes with completely different objectives.

Work Management = manage work execution. HOW TO DO THE WORK.

Strategy Management = manage the strategy to execute. WHAT WORK TO DO.

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Machines with rotating components usually rely on bearings to reduce friction in moving its parts around a fixed axis. The growing demand for more precise bearings to lower power consumption and heat generation, while simultaneously support increasing applied loads and/or higher speeds, has given place to the use of diverse surface engineering processes, specially coating technologies.

During the last three decades, advanced coatings have enjoyed a growing interest in several industrial bearing applications because they can be engineered to provide different properties like electrical insulation, low friction, and resistance to corrosion, surface initiated rolling contact fatigue, abrasive wear, and plastic deformation. The main surface engineering processes to deposit these coatings include traditional technologies such as dipping and liquid spraying, chemical conversion, galvanizing and electroless processes, as well as more sophisticated technologies such as thermal spraying, physical vapor deposition, diffusion, and ion implantation. However, the special characteristics of the bearing steel and the need to limit the deposition costs reduce the number of methods that can be practically used.

In this talk I will first introduce the four main areas where coatings can contribute to improve the performance of bearings made of standard bearing steel: lower friction, decreased wear, corrosion resistance, and electrical insulation. For each area I will review which coatings are industrially used, their possible industrial deposition methods, and their main mechanical and tribological properties. Examples of SKF coatings used to extend maintenance and life expectancy of specialized bearings will be described, like NoWear® (carbon-based nanostructured coating), Black Oxide (iron oxide conversion film), INSOCOAT® (aluminum oxide coating), and manganese phosphate films. I will finish the presentation discussing needs of specialty surface-treatment coatings in response to bearing application challenges.

Wherever moving components are in contact, the materials involved have to fulfil predefined wear and friction requirements. A viable and efficient approach to develop novel products using tribological materials characterisation to up-scale new or alternative conventional materials is not yet available. The project i-TRIBOMAT funded within the Horizon 2020 (GA Nr. 814494) bridges this gap between the traditional tribological lab-scale characterisation of materials, and the tribological requirements of a real-life application, thereby reducing costs and time-to-market, which supports the innovations within the European manufacturing industry.

The goal of i-TRIBOMAT is to develop the world’s largest user-driven open innovation test bed that enables versatile tribological characterisation of materials and the up-scaling of tribological material behaviour to industrial dimensions.

Therefore, new digital services will be developed and offered through a new legal entity as the Single Entry Point (SEP) to the customers.

The outstanding and new features and services of this SEP are:

• Biggest Tribology Test Center with access to tribological infrastructure of more than 100 tribometers and characterisation equipment with newly developed protocols, procedures and triboanalytics
  • This enables fast, harmonised and trusted tribological materials characterisation

• Secure IT-platform with integrated tribological materials data base
  • This enables data driven services like cloud data storage and sharing, data mining, big data analytics, fast report generation

• Web based Collaboration Interface with virtual workroom and ready to use tribo-models
  • This enables simulation based up-scaling of the materials behaviour on component level

Advances on technologies regarding acquisition, communication, storage and processing of data and information is leading to unprecedent impact regarding the potential to transform the way knowledge is generated from data and information sources, and the business models that can arose. Internet of Things is at the centre of this transformation and it also applies to tribology. This paper will explain the activities being carried out in order to reuse and enhance current IoT architectures and protocols to create an infrastructure providing support to a network of tribology devices linked to a data platform, with the aim of generating an open innovation test bed, where tribological resources even experiments and results are accessible in a standardized and interoperable way.  The paper will outline the design of a middleware able to support a network of tribo-connected devices, that should incorporate different features related to IoT architectures (Security, Connectivity, Heterogeneity, Dynamic adaptation and configuration, Data ownership and sovereignty, Intelligence,…), and that includes local edge connectors as well as generic edge to cloud data sharing mechanisms.  The paper will also include an outline of the configuration specifications that enable an harmonized interoperable information representation of main features related to the tribometers and their related experiments and services.

This paper presents a summary of the main tribological materials characterization services that the i-TRIBOMAT Open Innovation Test Bed offers to the European Industry. This article describes examples of different services, which mainly include tribological and surface characterization tests, data sharing services and modelling and virtual upscaling works. i-TRIBOMAT will provide the European Industry with all these characterisation tools, which will allow a better knowledge of the friction and wear behaviour of materials under a large variety of environmental conditions. Life-time prediction of components is another sort of services provided by i-TRIBOMAT. Such life-time prediction can be based on experimental tribotests and supported on database searches of previous data and/or computer simulations. In the future this will result in a better choice of materials for the design of mechanical parts and components.

In order to shorten time to market of products and to support new developments, the European Community is funding a HORIZON 2020 project called i-TRIBOMAT. In the field of tribology, renowned institutions combine their testing and analytical capabilities to provide the respective services. The later will be offered in Europe via a Single-Entry Point (SEP). Due to this combination of services, a testbed is created consisting of more than 100 tribometers. Thus, a large variety of testers exists, either commercially available or in-house built. Each tester is optimised to simulate a specific tribological contact situation. Currently, there is no standard available for the design of such testers. Especially, the way forces (normal load, friction force) and distances (e.g. stroke, linear wear) are measured, recorded and pre-processed differs from type to type. These forces and distances are essential for the determination of wear/ wear rates and coefficients of friction (COF), the core results of tribo-tests. This matter is complicated by the fact that e.g. for reciprocating motion, there are at least four different ways to determine COF. Depending on the testing conditions, these ways can lead to considerably different results. Currently, it is not obligatory to specify the method used for determining the COF.

In order to make data comparable, there is a need for measures which ensure that each tribometer is delivering similar, at best the same results under the same test conditions, irrespective of its manufacturer, design, location, determination method and even operator. The way forward are improved Round-Robin tests. First results and other challenges faced by creating comparable tribological data will be considered in the present contribution.

Lab to Field: Bridging the Gap between Bench and Engine

Frauscher, Marcella; Agocs, Adam; Budnyk, Serhiy; Ristic, Andjelka; Doerr, Nicole

AC2T research GmbH, Wiener Neustadt, Austria

Functionality and lifetime of engines – comprising engine components as well as the engine oil – are mostly based on time-consuming and expensive engine and chassis dynamometer bench tests. Empirical data gained from lab devices such as tribometers provide valuable fundamental knowledge but correlation with field performance is limited. Some limitations and challenges include long-term effects, such as oil degradation, but are often neglected due to resource restrictions. The “lab-to-field” approach aims at bridging the gap between laboratory bench testing and real world, field applications. A laboratory-based large-scale device for lubricant aging is proposed for the provision of sufficient quantities of a well-defined ‘used’ engine oil considered as test oil in engine and component test rigs. The example of a soot-contaminated oil from a diesel engine test rig shows how oils from the field are reproduced in the laboratory. The correlation between field and laboratory is determined by conventional oil parameters, molecular structure information provided by mass spectrometry, soot analysis and tribometrical experiments. The impact of engine oil condition on friction and wear is discussed, i.e., how nano-scale behavior determines macro-scale performance. 

Main topic:
Tribology  Friction and wear, Prediction of tribological performance
 

REWITEC® is a part of the CRODA group and develops an innovative silicon-based nano- and micro-particle surface treatment technology for engines, gears and bearings. The active particles use lubricants as a carrier and build through their adsorption a protective and repairing silicon-based coating on the surface. When applying the products treated systems can run better with reduced friction, wear, surface roughness and temperature. These effects lead to higher efficiency, great reliability and longer lifetime.

To develop and to improve the technology, REWITEC® works since many years closely with several research institutes and universities, which are able to perform tribological tests with high accuracy and reliability. In this presentation we would like to show our new tribological study about standstill damage of bearings.

Standstill damage are a well-known problem especially in wind turbines, but they occur generally in all systems, where vibrations appear during standstill. Although common lubricants help reduce the damage, they can’t prevent it or prevent it to a minimum, because of the very poor lubrication due to lack of movement in the system. For this reason, it’s useful and necessary to optimize classical lubricants by adding REWITEC® with its silicone-based nano- and micro-particles, which adsorb on the steel surface and stay on it, even if the lubrication is deficient. We have scientifically analyzed the behavior of REWITEC®-particles in standing systems through the so called False-Brinelling-Test in cooperation with the University of Mannheim, Germany. The experiment results show a reproducible significant wear reduction of up to 70 %. Furthermore, the Rewitec®-technology can not only reduce the damage for the future, but also partially repair already damaged surfaces. As a supplement to these scientific tests we also would like to present some technology applications in technical systems like wind turbines, that confirm the obtained scientific results.

• A new class of bio-based fluids, Estolides, have been developed and patented in the US. This technology was originally developed by scientists at the United States Department of Agriculture (USDA) over 20 years ago and is now owned and being commercialized by Biosynthetic Technologies LLC. These Estolides can be produced from a variety of bio-derived oils, for example non GMO Castor based fatty acids.

• These Estolides have been produced in a wide range of viscosities, with the current commercial products being ISO 22, ISO 150 and ISO 680. This makes them ideal for blending a wide range of lubricants, including hydraulic oils, industrial and automotive gear oils and greases.  They have renewable contents of up to 95% and biodegradability levels of greater than 70%, depending on viscosity.   

• The unique chemistry of Estolides provides base oils that address some of the issues often associated with bio based fluids, such as oxidative and hydrolytic stability. For this latter performance, Estolides have been shown to be comparable in extended tests, with high purity mineral oils and Polyalphaolefins.  High levels of oxidation stability has also been confirmed. The Estolides have also shown have excellent performance in elastomer compatibility.

• The quality of these products has enabled all of the grades to be established on the LUSC list as a base fluid for Ecolabel oils, as well as being registered with the NSF organisation as an HX-1 food grade component.

• Further performance testing is in progress.

1.      Introduction

Ionic liquids (ILs) are still a comparatively new class of substances with interesting profiles of properties, such as a high thermal stability, a low vapour pressure, incombustibility, and a comparable high surface tension. Due to the huge variety of possible ion combinations many properties can be adjusted to fit to a specific application.

2.      Ionic liquids as lubricants

Selected ionic liquids can influence also friction and wear in a positive way. Due to the striking properties as mentioned above, they are quite obviously interesting for a couple of special lubricant applications, such as high vacuum, extreme pressure, and/or extreme temperature environments.[1,2,3]

Because of their non-polar character PAO-oils are still a challenge in terms of miscibility with ILs. In our contribution we will report our latest results on approaches to mix ionic liquids with PAO-oils to improve their properties in beneficial way.

3.      Ionic Liquid mixtures as conductivity promoters

Ionic liquids are consisting entirely of ions. Because of their ionic character it is possible to generate an electric conductivity in lubricant formulations and to improve it by design.

Within the project WindpowerLife (funded by the German Federal Ministry of Economic Affairs and Energy) it is the challenge to improve and to quantify these properties of conductive lubricants further.[4]

In our contribution we will present the latest status and recent results of our joint research project. Furthermore, we’ll give an outlook on the status of commercialization of this technology.

4.      References

[1]          B. S. Phillips, J. S. Zabinski, Tribology Letters, 2004, 17, 533.

[2]          I. Minami, Molecules 2009, 14, 2286.

[3]          M.-D. Bermúdez, A.-E. Jiménez, J. Sanes, F.-J. Carrión Molecules, 2009, 14, 2888.

[4]          Verbundvorhaben: WindPower-Life - Erhöhung der Lebensdauer, Belastbarkeit und Zuverlässigkeit von Lager- und Getriebekomponenten in Windkraftanlagen; Teilvorhaben:

Lubrication oil is not only an important factor for internal combustion engine wear but also for emission control system performance and durability. In the present work we provide an overview of important lubrication oil- nanoparticle issues in combustion engines including: the nature of exhaust nanoparticle emissions (especially non-regulated particles in the <23 nm range), oil-derived ash and its impact on particulate filters and catalysts and characterization of soot-in-oil nanoparticles.  An array of experimental techniques including advanced nanoparticle measurement instrumentation, environmental and high resolution Transmission Electron Microscopy, in-situ micro Raman and FTIR spectroscopy are employed to analyze particle structure, size, morphology and composition and advance our understanding towards achieving better performance and environmental compliance of lubrication systems in combustion engines.

New lubricants formulation as a result of extensive experimental study is a challenge derived from the demanding circumstances of efficient engine operation. Effective lubrication can reduce friction, increase efficiency and reduce emissions. The lubricant has to perform these qualities, maintain a hydrodynamic film between the piston-ring and liner, reduce film emissions, increase load capacity taking into account the effect of cavitation and contribute to total efficiency. The shear-thinning properties affect the appearance of cavitation and viscosity variation with temperature increase alters cavitation initiation and the resulting shapes during the stroke. Different cavitation shapes on the surface of the piston-ring affect the total ring load carrying capacity.

In a simplified single-ring test rig a steady piston-ring section is placed under a flat surface used as a reciprocating liner. This approach separates and simplifies the tribological conditions from the fundamental and unsteady circumstances encountered in production piston engines. Thus, many uncertainties are ignored (starvation, oil transport, ring - piston dynamics, thermal - elastic deformations and blowby) following piston movement. Reliable and repeatable results can be generated and, simultaneously, the film characteristics can be examined in isolation.

Sensors measure film pressure, thickness (optical –LIF, electrical-capacitance), friction and imaging, provide excessive parametric results: speed, load, temperature, rings geometry, lubricant properties with the addition of different sets of lubricants and properties are examined.

This study presents useful parametric results showing the effect of different lubricants and setups on the measurements derived by the sensors. It is important to examine the lubricant properties and their temperature variation along with the effect of the shear-thinning properties on cavitation. This investigation studies the variation of load carrying capacity according to the LIF measurements and assesses the rheological behavior of chemical additives with a view to establishing the likely performance gains in new lubricant formulations.

The EU has set the renewable energy target at 32 % for year 2030 by the Post-2020 Renewable Energy Directive. Wind power has an important role to fulfil the renewable energy demand in the future. The current trend is to build bigger and more powerful wind turbines with request of longer lifetime expectancy. Bigger turbines mean higher power densities experienced by the critical components of the wind turbine. In order to fulfil the future requirements new materials that meet the technical requirements are needed for designs. As the new solutions are explored, there is also a need to develop advanced testing methodologies and design tools to help designers to find innovative and reliable solutions and bring them faster to commercialization stage.

The gear set is one of the main components in wind turbine and it´s reliable performance is essential for the power production. The size of gear sets has been decreasing and the power density has greatly increased over the last decades and the similar trend is continuously increasing. This influences the gear design and material selection of the critical components. One example is the use of sliding bearings instead of rolling element bearings in the gear designs. The use of novel material solutions require extensive evaluation and testing of material properties and new tools are required to bridge the gap between laboratory-scale test results and the product scale performance of new solutions. In i-TRIBOMAT project, we are developing modelling based Lab-to-Field upscaling functionalities to speed up the design phase and enable the upscaling of new material solutions to actual products. The Lab-to-Field upscaling functionalities are generated based on experimental tests and computer simulations carried out in the laboratory scale and in the pilots scale generating the basis for the upscaling of new materials for journal bearings.

Elastomeric seals are components mounted in most of the devices were a fluid has to be sealed. Their use is extended to a wide range of industries such as the automotive, energy, aerospace and manufacturing industries. They are critical components in engines, landing gears, flight controls, airframes, transmissions and pumps, among others. Their function is to avoid the transfer of fluid from one area of the device to another, and even to avoid the entry of dirt particles into the system. Sealing systems usually comprise the combination of different seal types. Rod seals, piston seals, wiper seals, guide rings and static seals are usually combined in order to avoid fluid leakages and the entry of dust into the system.

Seal geometry and material research is essential to reach a compromise between sealing and good lubrication. Several studies on sealing systems resulted in a wide variety of seal geometries and materials, and a better knowledge about the performance of sealing components during operation. However, considering that the market is continuously demanding for higher performance applications, thermal resistance of polymeric seals is still a bottleneck in many applications. Moreover, due to the wide range of parameters involved in every sealing operation, designing the most appropriate sealing system for a specific application is a challenge. And due to the complexity of non-linear material behaviour, there is a lack of standards for testing tribologically polymeric seals and materials in general, and therefore wear mechanisms of seals are not completely well understood even nowadays.

Aim of this presentation is to present a summary of the main challenges in sealing technology and some case studies.

The presentation will firstly present the activities of the EUMAT, the European Technology Platform for Advanced Engineering Materials and Technologies and the Alliance for Materials (A4M), addressing future materials research challenges. It will be presented the reflection paper, elaborated by EUMAT and A4M, addressing the role of materials in the post-COVID society. The paper summarizes the positioning, potential solutions, and recommendations that stem from the European Materials community (Alliance for Materials A4M) towards Horizon Europe in the Post-COVID scenario. The paper compiles existing Strategic Research Agendas (SRAs) of different materials stakeholders and address a specific reflection in the context of the current COVID19 pandemic. It puts forward proposals for strategic research and innovation activities to the European Commission, Member States, and the European Parliament, considering the objectives of the Green Deal Priorities and Recovery Plan.

The second part of the presentation will deal with research financing opportunities in Horizon Europe, M- Eranet Calls, Eureka and Eurostars, as catalyst for research developments in the field of tribology, lubrication and condition monitoring.

The continuous increase in technological and quality requirements from industry demands better lubricants, that can withstand higher stress and longer oil drain intervals. Also, environmental concern pushes to the optimization of lubricant lifecycle. But, at the same time, the continuous focus on the lubricated equipment health and its maintenance procedures are still the main concern in factories. Also, Industry 4.0 is a leading trend nowadays and lubrication is not out of the digitalization need. The combination of all these requirements creates the necessity to take advantage of new technology in the lubrication services.

Online lubricant monitoring offers added value in the whole lubricant supply and use chain. From the oil factory to the end-of-life lubricant drain, lubricant monitoring sensors offer added value to the customer. Several examples of the possible applications are fresh lubricant traceability, on-line filtration system monitoring, real-time flushing control, in-service lubricant condition digitalization, and asset condition remote diagnosis.

In our work, we are going to show the benefits that online technology offers for asset condition and lubricant lifecycle monitoring, supported by examples from different industries.

The application of innovative technology in lubrication services reduces operational risk and offers the possibility to create new and improved services to deal with stringent industry demands.

Connecting your fluid analysis program to your maintenance management software can set you on the path of improvement in your reliability journey. Imagine the value of reviewing fluid analysis data alongside on-board sensor data, work history, operator reports, equipment operating conditions and the results of other testing methods, such as vibration, thermography, ultrasound, etc. Understanding the health of your assets and aligning maintenance priorities is now on a whole new and improved level.

Other benefits of connecting this data include the ability to truly move beyond individual reports and narrow the focus of needed maintenance activities that result in improved reliability and increased availability of your assets.

Learn more about these capabilities, along with the value of Pareto charts and Scattergrams in this exciting, fast-paced session

The continuous progress of Industry 4.0 has resulted in the development of connected and intelligent machines, equipment and components, capable of providing information for the decision making on their maintenance. And the ‘data’ is a vital element in this concept. This will allow intelligence to be provided to the systems through the facilitating technologies for analysis, extraction of indicators and integration of algorithms. This allows the state of health detecting anomalies and failures in early phases to be established.

Here lies the great challenge and the starting point that begins the journey towards intelligent equipment, such as using the data from the beginning in the manufacturer's facilities. A new business model is therefore opened based on the provision of maintenance services in its equipment (servitization) throughout its useful life.

However, there is great complexity in creating suitable environments for predicting failure. This forces processes of learning of the behavior to be developed in the use of the equipment/machines and to develop the knowledge necessary to interpret the signals that these provide to be able to infer the mechanisms of degradation and fault existing from the earliest phases (start-up of the equipment and machines).

This article shows how to extract knowledge from the initial stages to model the behavior of the system since its implementation. To this end, the protocol for testing and procedures for data acquisition, indicator extraction and knowledge generation on the state of the machine is initially defined. The work proposes a method that allows the state of the equipment to be classified through its comparison with a normality defined and quantified pattern from the beginning of its life through a series of facilitating technologies for data analysis.

1.  Introduction

The most common ageing mechanism for lubricating oils and hydraulic fluids is oil oxidation. The standard test method for oxidation in-service oils is based on FT-IR (e.g. DIN 51453). It is only a question of time and the generation of varnish like deposits lead to valve or filter problems in high-pressure hydraulics with sensitive servo or proportional valves, complex circulating lubrication systems such as turbines, turbo compressors, paper machines, large gearboxes etc. This produces very costly unscheduled downtimes.

2. Oil Oxidation

Oil oxidation is mainly driven by elevated temperatures and the catalytic effect of contaminants like water and metals and leads at the end to acid and deposit generation (figure 1).

Figure 1: Autooxidation process (Korcek)

2.1. Conventional oil condition monitoring methods

Basic detection methods of oil oxidation are the measurement of

• Kinematic viscosity
• Acid Number
• Infrared oxidation

It is shown, that especially in oils from machines of large oil volumes this methods are not suitable for a reliable detection of oil oxidation on an early stage.

2.2. A new method for Oxidation detection

The oxidation level in industrial applications like hydraulic systems, gearboxes or circulating lubrication systems is appr. 10 – 20 times lower than in combustion engines. Therefore, the single wave number based DIN oxidation test method is not able to detect oxidation in industrial applications reliable. Considering this, the authors developed an area based FT-IR method which provides a good trend based forecast on oxidation based oil ageing process (figure 2).

(BFigure 2: Oxidation by Single Wave Number compared to Area

3. Examples

The presentation shows, based on practical examples from different applications, how using this new method in combination with other methods to recognize oxidation based problems on an early stage by manageable costs.

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The classical tribological systems which are used in cold forming are still based on zinc phosphate as a separation layer and soap as a lubricant. Due to the globalization more and more processes are required following a globalized environmental protection and chemical registration concept. Therefore, the search for resource-efficient and environmentally friendly pretreatment concepts in cold forming are essential to fulfill these demands. Globally seen, there are different development routes to gain phosphate free tribological systems. On one hand, lubricants have been developed which are working without a conversion layer but leading to less forming performance which is often unacceptable out of profitability. On the other hand, there is the possibility to use a zinc phosphate free conversion coating layer to realize a phosphate free tribological system, without leaving the common system consisting out of a separation layer with a lubricant on top through remaining the same performance known from common systems. Beside this, it is discussed how a further development concept of this system leads to easier and sustainable processes introducing a reactive lubricant concept.

Our technical world is constantly changing. Global crises like the oil crisis in the 1970s resulted in an increased demand for fuel economy on vehicles. Since the 1990s, environmental concerns and emission limits prompted engine innovations that have reduced soot particles, NOx, Hydrocarbon and CO emissions. This led to completely new types of engine oils with additive technologies that were unthinkable decades ago. During the same period, industry too has advanced: constantly increasing demands for increased productivity have led to high-performance systems for hydraulics, transmissions, compressors, etc. Here too, lubricant manufacturers have found the answer to the new requirements with new high-performance lubricants and are continuing to work on new solutions.

But what happens in commercial oil analysis programs? Why were they introduced? How have they been developed? What are the trends for the future? How can oil analysis support users, the lubricant or the OEM industry, in meeting the constantly growing demands? What is the answer of oil condition monitoring to the challenge of the next industrial revolution, industry 4.0 and the Internet of Things?

This lecture examines the evolution of oil analysis and demonstrates how new approaches will meet the constantly growing demands of customers with regard to increased productivity and effectiveness of machines and systems, whilst taking into account the latest innovations.

The use of lightweight materials in the automotive industry has experienced a rapid growth in recent years. For instance, the reduction in vehicle weight has led  to a reduction in fuel consumption and, consequently, a decrease in CO2 emissions. Aluminum-silicon (Al-Si) cast alloys are widely used in the automotive industry due to their outstanding properties, including their low density, high strength-to-weight ratio and excellent castability. Nevertheless, their use is very limited due to their low wear and corrosion resistance.

Plasma Electrolytic Oxidation (PEO) is an advanced surface engineering technology to produce protective ceramic coatings on lightweight metals, such as Al, Ti and Mg alloys. The main advantages of PEO coatings are their high hardness and thickness, and superior wear and corrosion resistances. Furthermore, this technique is environmentally friendly, which makes PEO a promising technology.

In the present work, PEO coatings have been developed through the formulation of new electrolytes, with the aim of improving the surface properties of different Al-Si alloys. Moreover, the performance of the coatings developed with the new electrolytes has been compared with the ones obtained using a commercial electrolyte. Despite the challenges associated with the development of PEO coatings on Al-Si alloys, dense and homogenous layers have been obtained. Reciprocating wear tests were carried out in order to evaluate the tribological performance of the different PEO coatings, and potentiodynamic polarization and electrochemical impedance spectroscopy studies were performed to analyze their corrosion resistance.

Finally, in order to evaluate the performance of the PEO coatings under real working conditions, samples obtained from real Al-Si cylinder liners have been coated and their wear resistance has been compared with the currently employed Al-Si and cast iron liners. For that purpose, tribological tests simulating the real contact between the engine cylinder liner and the piston ring have been performed.

The wear damage produced in a railway system changes both wheel and rail assets profiles. These profiles play an important role regarding safety against derailment and consequently, it is important not to exceed the security thresholds of some parameters.
The employed corrective maintenance tasks to recover the original profiles are rail grinding and wheel turning. At the same time, lubrication plays an important role to manage wear damage as preventive maintenance. With the aim of reducing the Life Cycle Cost (LCC) associated with traditional maintenance, predictive methodologies are being developed making use of tested wear rates.

Scaled-test benches are a good tool for wheel-rail interaction assessment but with some disadvantages for wear damage characterization. Most of the wear rate characterizations are carried out with twin-disc machines. In twin-disc tests, the contact patch between specimens is different regarding a real wheel-rail contact under the same equivalent conditions. This is mainly due to the geometry of discs, which generally have a flat surface that helps to maintain a constant normal pressure.

Equivalent conditions are calculated by means of Hertz theory to obtain the same maximum normal pressure but wear is due to the sliding velocity between solids. The friction coefficient influences the ratio of sliding area and contact patch area. This ratio is assessed by solving the tangential problem to calculate shear stresses. The highest sliding area is more wear is produced.

For saturated conditions, the sliding area is equal to contact patch area but creepages are generally low in railway dynamics. Figure 1 and Figure 2 show the assessment of contact conditions for wheel-rail and twin-disc respectively. A friction coefficient at saturation of 0.48 gives a sliding ratio four times higher for the wheel-rail case with a longitudinal creepage of 0.2%.

Figure 1. Wheel-rail contact.

Figure 2. Twin-disc contact.

Failure of engineering materials due to fatigue, fretting, wear, corrosion and erosion initiates from the surface of the materials and the structure and properties of the surface influences the product performance. Grain refinement by severe plastic deformation in metallic materials is reported to enhance their mechanical properties and resistance to surface damage. Controlled ball impact peening, a novel surface modification process was developed to generate a nanocrystalline surface layer on the surface of the metallic materials. This article describes the fretting wear characteristics of controlled ball impact treated AISI 304 stainless steel samples under dry sliding condition. The grain size of the top nanocrystalline layer is about 10 ± 2 nm. Fretting wear studies were performed on the untreated and controlled ball impact treated stainless steel samples (i.e., as-treated samples) using a steel counterbody at constant slip amplitude and at different applied normal loads using ball-on-flat configuration. The controlled ball impact treated stainless steel sample shows decreased steady state tangential force coefficient, wear volume and specific wear rate compared to the untreated coarse grain samples. The increased substrate strength and the presence of compressive residual stress in the treated samples prolonged the crack initiation. Crack tip blunting retards the crack propagation resulting in decreased wear debris formation and wear volume. The worn surface morphology of the fretted samples at low applied normal loads revealed a complex adhesion and oxidation type of wear mechanism and at high applied normal loads abrasion was found to be a dominant wear mechanism.

Surface Mechanical Attrition Treatment (SMAT) a novel surface modification process uses a large number of hardened steel balls located at the bottom of a cylinder-shaped chamber. The steel balls are resonated by the vibration generator and the steel balls impact the surface of the metallic materials without modifying the surface chemistry. This article describes the influence of surface mechanical attrition treatment on the reciprocating sliding and fretting wear resistance of aluminium alloy in the as-peened condition and untreated aluminium samples using                    ball-on-flat configuration (steel counterbody) under unlubricated condition at different applied normal loads and peening durations. The SMAT experiments were carried out using 5 mm diameter 316 L stainless steel ball at 50 Hz frequency and in vacuum (- 0.1 MPa) for peening duration of 15, 30 and 45 minutes. Samples of dimensions 80 mm x 35 mm surface area obtained from a 6 mm thick aluminium plate polished using different grades of silicon carbide abrasive paper and alumina powder were used for SMAT treatment. Microstructural investigation of the SMAT treated aluminium samples revealed the formation of nanostructured grains on the top treated surface layer with heavily deformed surface layers and the mean grain size of the surface layer is approximately 10 ± 4 nm. The dry sliding wear rate increases as the load and grain size increases and decreases with increase in peening duration. The dry sliding wear scar morphology of the worn surfaces observed using scanning electron microscope reveal the dominant adhesive and mild abrasive form of wear. The dry sliding wear resistance and fretting wear resistance increases by 13 – 38 % and 10 – 48 % in SMAT treated samples for different peening durations and test conditions respectively.

Thanks to high bonding energy between carbon and fluorine atoms (460 kJ/mol for covalent C-F bond, compared to 410 kJ/mol for covalent C-H bond), fluorine-containing lubricants possess excellent stability under harsh conditions. Nowadays, they enjoy several applications in task-specific purposes as liquid lubricants or solid lubricants including low friction coatings. However, degradation of fluorine-containing lubricants under tribological conditions has been reported by different researchers. It occurs relatively lower temperatures compared to the decomposition under static conditions. Typical degradation products such as low molecular organo-fluorine compounds in gas phase as well as metal fluorides on the rubbed surface have been identified using instrumental analyses. These evidences indicate the dissociation of C-F bond(s), while the process has not yet been explained with regards to its reaction mechanism.

                       The previous work on lubrication performances of room-temperature ionic liquids using a vacuum tribo-tester interfaced with mass spectroscopy revealed that the anionic moieties prone to react with metals under tribological stresses, yielding a boundary film. The resultant film provides lubrication properties. Careful analysis of in-situ mass spectroscopy monitored throughout the test indicated decomposition of cationic moiety occurs during steady state of the lubrication. We found that certain process during the running-in stage of lubrication are key to understand the tribo-chemical reaction mechanism.

            In this work, we discussed step-by-step reaction mechanism of anionic and cationic moieties with emphasis of reaction intermediates. Several hypothesized mechanisms were evaluated by comparing the energy for each unit reaction based on a quantum mechanical calculation. In this way, the bond dissociation process through radical or ionic intermediates were discussed. The influence of the boundary film on further reactions was clarified. This work enables in depth study of the degradation mechanism of fluorine-containing lubricants.

Small is beautiful?!   Or:  What it takes to survive and flourish as SME[1] in the lubricants market

Hans J.Gerdes, Leader Business Development, email: gerdes@metall-chemie.com

1. Introduction

It was already hard to compete against the “big Players” in the market with their reach, cost advantage and brand awareness. Covid-19 made it even more difficult to compete, as retained earnings might be limited.

However, a formidable share of the market is taken by SME. The paper will provide a view on few strategies that work to survive and flourish.

2.            Scope of paper

The paper is focussed on both lubricants and lubricant additive suppliers and marketers. Usually nobody will compete in both markets at the same time, and three are distinctive differences between the two markets. Common among both (and, generally speaking, among any B2B operation):

• Do you have your targeting right: which area of lubricants do you want to be successful in, can you quantify your market potential
• Is your offer distinct: what are your edges, are they distinct, can you put them down in few words
• Is your delivery model suited to fulfil your promise

Some hard market data will be presented for the lubricant and derived additive markets; and some selected offer strategies to survive and flourish will be shared in a humorous, entertaining way. 

3. About the author

Hans Gerdes brings along a wealth of experience of almost 30 years in lubricants, most of his career was spent in the largest lubricant company in the world, before he became the lead for a start-up company in lubricants additives, beginning from scratch. At present he leads the business development for innovation.

References

[1]       SME: small- and medium-sized enterprises

This paper focuses on ensuring that the sampling valve installed on the equipment is providing representative and repeatable data fundamental to critical decision-making from your oil analysis report.

Examples of data variance, depending on the method and location used will be provided in areas such as engines, hydraulics, compressors, gearboxes and reservoirs.

The discussion will include what best practices to include and how sampling programs can be compromised without proper training, procedures and supervision

Rotating equipment reliability is very crucial in today’s highly competitive global economy. Lube and hydraulic oils’ cleanliness plays a major role in keeping critical rotating equipment items running reliably.

Apart from transmitting power in hydraulic systems, the primary function of lube and hydraulic oils is minimizing friction and reduce wear. The effectiveness in preventing wear can be seriously compromised by the presence of contaminants such as particulates and water in the oil.

This presentation focuses on particulate contamination, which is the most destructive type of contaminants. It identifies their sources, which are contaminated new oil, built-in contamination, ingested contamination and internally-generated contamination.

It describes in details the most effective test for quantifying particulate contamination and assessing system cleanliness. It also guides the audience on how to systematically set cleanliness targets for different types of equipment taking into account system pressure, environment, life expectancy, maintenance and production loss costs in case of failure, and safety liability.

The presentation details the improvements and measures to be taken to minimize solid particles contamination such as proper storage and handling, new oil filtering and system hardware modifications. This part also shows the importance of proper cleaning and flushing after major overhauls for faster commissioning, greater operational stability, and longer service life.

The presentation displays the effect of improving oil cleanliness on extending machine life based on studies performed in many industries as all show dramatic extensions in expected machinery life. In one example, a reduction of particles larger than 10 µ from 1000/ml to 100/ml resulted in a 5-fold increase in machine life, which must be an attractive return on cleanup investment.

Particles, water and varnish are well known as the contaminants responsible to increase maintenance work of a system which provoke high economic lost and environmental detrimental effects by the oil change. Valves blocked, gas turbine turn on forced when the oil is cool, heat exchanger working deficiently and plug of in-line filters are the most typical problems in a gas or steam turbine where the varnish is the main responsible for this behaviour in a turbine. All of them are consequence of the oil aging and will be controlled when the MPC value is below dE 15.

Everybody have heard about varnish, however, there are lots of doubts about its provenance and composition. Is the varnish an external or internal contaminant? is it ingress or created in the oil? Why the varnish precipitate from the oil? Why the varnish precipitate easily in the cooler places of a system?

A deeply oil oxidation understanding is the key to know how we can control and solve these problems avoiding them all to appear again. Oxygen and temperature are the main precursors for changing the oil properties and, therefore they are the responsible for all the questions asked above.

Therefore, varnish control tools are strongly recommended to keep under control the varnish growing trend which is produced by the unstoppable oil oxidation reaction.

Stern-tube bearings in propeller-driven ships are generally lubricated by the surrounding water, removing the need for a rear seal. Such bearings are commonly referred to as Cutlass bearings.  The bearings consist of a series of grooves, or flutes, and a number of load-carrying areas called staves.  This presentation discusses some work performed in the Jost Institute for Tribotechnology which seeks to develop a design guide for these bearings. The method includes a new, 3D, finite element (FE) approach for soft elasto-hydrodynamic (EHL) predictive-modelling of generated pressures. Model predictions compare favourably with experimental data. It is shown that the modulus of elasticity of the rubber has no influence on the minimum film thickness. An equation relating dimensionless film thickness to dimensionless load, clearance ratio and numbers of staves is presented.  The effects of out-of-roundness are also discussed.

The advent of the autonomous haul truck fleets has delivered savings in the cost of operations and greater revenues through higher efficiencies in the tons of ore moved. Driverless haul trucks place an increased reliance on automated systems that leverage IoT sensors, wireless networks, edge-computing and mobile apps to provide real-time condition data and actionable information. This presentation introduces a disruptive technology that offers global mining operations an end-to-end integrated oil condition monitoring, data analytics and LIVE autonomous oil sampling system. 

The SmartOil-M™ Series from LogiLube integrates off-the-shelf IoT sensors to provide real-time condition monitoring of fluid properties by measuring physical attributes in situ. Powered by a robust edge-computer, SmartOil-M™ also integrates an auto-sampling function that can be utilized to collect LIVE samples from which to calibrate the sensors, or collect fluid samples for subsequent independent lab analysis. The sample interval period is user programmable, and a manual sample event can be triggered remotely from a safe distance via a companion mobile app running on a Bluetooth® connected tablet. Historical data can be viewed or uploaded to the client's network for further analytics.

The current trend in Oil Condition Monitoring (OCM) is the use of sensors to monitorize the oil performance, based on spectroscopic techniques such as Fourier Transformed Infrared (FT-IR) spectroscopy or electrochemical procedures. However, the transition from classical techniques/procedures to new alternatives is not easy due to different factors, such as the requiered number of samples, technical limitations and signal reproducibility.

Focused on engine oils, FT-IR is one of the most important techniques to determine the performance of the engine oil, thanks to the variety of parameters that this technique can measure: oxidation, nitration, soot content… According to that, some researchers are developing studies to assess the FT-IR technique to detect or quantify other parameters that cannot be determined directly from the spectrum. One of these parameters is the Total Acid Number (TAN), which impact on some engine metals corrosion wear has been corroborated.

To get a correlation between FT-IR spectra and TAN (according to new ASTM D8045) are required a huge number of samples to generate a robust mathematic model. However, this could be a problem, due to the complexity to manage all this information. In this research work, it was necessary to study the spectrum and apply some criteria to reduce the amount of data: select those sensible regions that can affect the TAN estimation and disscard those regions with no or low relevance.

Results obtained have shown that it is possible to obtain a mathematical model from FT-IR data fitting values obtained by thermometric measurements that allows to determine quite accurately the TAN value and keep a control of its level along the oil drain interval. Furthermore, the implementation of this methodology in the routine analysis of engine oil samples can let to generate a benefit to the OCM in terms of costs and time for the analysis.

Lubricant oils used in engines and in industrial machinery are formulated from a range of different base oils to which several additives are added to improve lifetime and performance of the oil.

Degradation of lubricant oils occurs through different chemical and physical processes: base oil degradation, oil contamination and/or additive depletion. The dominant degradation mechanism is determined by several factors, such as oil formulation, pressure, operating temperature, mechanical shear and more. The range of the oil formulations and of the parameters governing the oils degradation, make the oil aging process complex and difficult to monitor on-line. However, different aging states are characterised by different volatile compounds emitted by the oil, and headspace analysis seems to be a viable solution for on-line degradation monitoring.

We have developed an artificial olfactory system for oil-degradation monitoring by the evaluation of the concentration of molecular compounds in the lubricant headspace. The system has already proved the capability to detect differences in the volatile compounds emitted by new SAE 10W-40 engine oil and the same oil after having run a few miles.

This paper describes new experiments carried out on lubricant oils composed of different base oils: synthetic oil and mineral oil. All the oils are artificially aged by oxidative degradation at different temperatures. Samples of the oils at different degradation stages are collected at fixed times and are analysed using the artificial olfactory device. These experiments aim to determine the ability of the system to identify different aging phases of the oils, with good levels of resolution, for a range of different oil formulations. The same oil samples are characterised through standard laboratory viscosity tests to compare the results of the odour analysis. The results of the measurements are presented and discussed.

Friction and wear performance of used and artificially altered hydraulic oils

Frauscher, Marcella1; Schneider, Ameneh2; Kolbas, Daria3; Dörr, Nicole1; Budnyk, Serhiy1; Novotny-Farkas, Franz4

1. AC2T research GmbH, Wiener Neustadt, Austria.

2. Optimol Instruments Prueftechnik GmbH, Munich, Germany.

3. Gubkin Russian State University of Oil and Gas, Moscow, Russian Federation.

4. Engineer Consultant, Schwechat, Austria.

Short-time tribometrical tests were applied to characterize fresh and the respective used or artificially altered hydraulic oils according to friction behaviour and wear formation. Hydraulic oils with different degrees of degradation were obtained from thermal-oxidative stability tests, Bosch Rexroth pump test and from the field after up to 40,000 operating hours. For tribometrical evaluation, a steel-steel contact with ball-on-disk configuration in the Schwing-Reib-Verschleiss-Tribometer SRV® 5 was applied. The findings obtained with tribometrical tests were correlated with condition monitoring data of the lubricants. While conventional oil characterization did not show tremendous oil degradation compared to the fresh oil, tribometrical test results differentiated between fresh and used oil condition. For the comprehensive understanding of the observed behaviour, surface characterization and high-resolution mass spectrometry were performed.

Topics (https://www.lubmat.org/en/main-topics)

Maintenance 4.0 and condition monitoring  Machinery diagnostics through lubricant analysis

Keywords

Hydraulic Fluids, Oil Condition Monitoring, Boundary Lubrication

Gas engines require to burn a variety of gases (fuels) which are characterized in some applications by having butane, methane and carbon dioxide and which frequently contains halogens such as fluorine and chlorine, as well as the presence of siloxane compounds, which cause a very “hostile” environment for the lubricant. Understanding the behavior of these engines, gas fuel combustion process, which results in the accumulation of sulfate products which are an indicator of oil degradation caused by oxidation of sulfur in the oil and sulfur in fuel are essential to make a correct condition monitoring and diagnostic.

In this study, a representative sample have been studied in order to evaluate the critical role sulfation process play in gas engine oil performance, in addition to the review of several EOMs, in order to get a better understanding of the degradation process to achieve maximum efficiency and long life from the engines.

The results of this study, show the need to re-evaluate some EOMs that have been studied and, above all include an essential parameter in the diagnosis of gas engines such as sulfation, in order to make the right decisions in the maintenance plans and in determining overall machinery health and in determining additive depletion.

Keywords. Ionic liquids, encapsulation, heat transfer fluid, thermal conductivity

Encapsulated materials have been used in different sectors and with diverse applications, since they allow the formulation of materials with new or improved properties. The type of materials to be encapsulated depends on the desired property in the final product. The active materials to encapsulate go from phase change materials, nanoparticles…

 This encapsulation and subsequent dispersion allows the formulation of materials with new or improved properties. In the development of this technology, it is of great interest to obtain capsules in the micrometric range, since their subsequent dispersion facilitates an effective homogenization of the active material throughout the matrix. 

Despite of the advantages of IL, these compounds present some milestones, immiscibility, water absorption, corrosion potential, which limit it used, so as strategy to block these mentioned disadvantages, the microencapsulation appears to be the accurate strategy. The encapsulation of phosphonium phosphate in inorganic microspheres is demonstrated.  This method is based on the encapsulation of ionic liquid within a silicon shell by SOL-GEL technique. The microcapsules were characterized by scanning electron microscopy, thermal gravimetric analysis, given capsules with a diameter of 155nm, and with an active IL content up to 42%.

The potential of these new innovative additives has been tested in heat transfer fluid increasing thermal conductivity up to 5% with no evidence of IL migration or shell nature degeneration

REFERENCES

Vinh Duy Cao. Microencapsulated phase change materials for enhancing the thermal performance of Portland cement concrete and geopolymer concrete for passive building applications. Energy Conversion and Management, Volume 133, 1 February 2017, Pages 56-66

This research deals with the wetting properties of 12 different ionic liquids (ILs): trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate [P6,6,6,14][(iC8)2PO2], trihexyltetradecylphosphonium bis(2-ethylhexyl)phosphate [P6,6,6,14][BEHP], trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl) imide [P6,6,6,14][NTf2], trihexyltetradecylphosphonium dicyanamide [P6,6,6,14][DCA], trihexyltetradecylphosphonium chloride [P6,6,6,14][Cl], methyltrioctylammoniumbis(trifluoromethylsulfonyl)imide [N8,8,8,1][NTf2], methyltrioctylammonium caproate [N8,8,8,1][C6:0], methyltrioctylammonium caprylate [N8,8,8,1][C8:0], methyltrioctylammonium laurate [N8,8,8,1][C12:0], methyltrioctylammonium palmitate [N8,8,8,1][C16:0], methyltrioctylammonium stearate [N8,8,8,1][C18:0] and methyltrioctylammonium oleate [N8,8,8,1][C18:1]. The surface tension was analyzed using the Gibbs free energy in a temperature range of 293−333 K and the contact angle was measured on AISI 52100 steel using dynamic sessile drop tests at room temperature. In addition, the polarity fraction (PF) and the spreading parameter (SP) were calculated with the aim of improving the wettability understanding of these ILs.

Surface tension results showed that the increase of the alkyl chain length in the 6 fatty acids anion-based ionic liquids (FAILs) rise surface tension in a similar way that in hydrocarbons. But longer alkyl chain length and anion size in the other 6 ILs causes a dispersion of the charge and the surface tension values decreases. Regarding contact angle results, all cases studied are time-dependent and therefore this property does not perfectly characterize the solid-liquid interaction. Polarity fraction values varied between 0.27 and 0.43, being the 6 FAILs the ones with lower values. Although all 12 ILs “wet” the surface (SP>0), the values obtained with FAILs almost double those obtained for traditional ionic liquids. This better affinity with less polar metallic surfaces such as steel is due to the lower polarity of this novel family of ionic liquids, which makes them better from the wettability point of view. Finally, additional wetting parameters like SP became a helpful outcome for understanding the wetting performance of ILs.

Today’s highly competitive market demands automotive and heavy-duty industries to increase efficiency, reduce downtime and emission. Core parts of various mechanisms are exposed to extreme conditions: temperature, load and vibration. To meet industry requirements the use of the high-performance additive for lubricant and grease production   to protect equipment under extreme conditions, has significant importance. It is well known that in order to fulfill these requirements, beside a suitable thickener type and base fluid, several types of additives are used e.g. extreme pressure, anti-wear, tackifier, friction modifier, copper passivator etc... However, combination of multiple components in many cases may give antagonistic effect and result in significantly increased cost, especially in a tribological contact.

The aim of this work was to investigate if high performance greases could be formulated by minimizing the number of the components that are typically used. Hence only four components were used: Thickener, Base oil, Antioxidant and submicron spherical nanoparticles. One of the areas of this research was to understand if there is any relationship between the thickener content of various type of greases and the performance of the nanoparticles on the tribological contacts in a rotational movement e.g. ball on disc.

The outcome of the performance study suggests how to formulate simpler lubricating greases, without any compromise in performance, for use in various industrial applications.

Friction is a global phenomenon of transformation and energy dissipation. The friction contact has system properties. During operation, the friction contact evolves. The evolution of the friction contact forms an elementary tribosystem – the critical volume of friction. Quantitative regularities of the evolution of the friction contact (elementary tribosystem) are subordinated to the energy balance equation. From thermodynamic point of view friction is a competition of two simultaneous, interconnected and opposite tendencies of accumulating latent (potential) energy  of various kinds of defects and damages of contact volumes structures and releasing (dissipation) energy due to various relaxation processes. The structural-energy interpretation and regularities of evolution of tribological contact (elementary tribosystem) are discussed. As the result of most full evolution of contact the unique nanostructure (subtribosystems) is formed and the basis of which is one mechanical (nano) quantum. Mechanical quantum represents the least structural form of solid material body in conditions of plastic deformation. Mechanical quantum is dynamic oscillator of dissipative friction structures. The universal size of a mechanical quantum (8103,08396… atoms) is considered as a universal constant. The nano-quantum model of the surfaces damping is proposed. Calculations have shown the number of such mechanical quanta (elementary nanostructures) within the elementary tribosystem’s volume to be about 63 millions, which is close to the safe number of fatigue cycles. According to a model of quantum surface damping at friction in state of most complete evolution (adaptation) of elementary tribosystem all mechanical quanta with the exception of one elasticity and reversibly transform energy of outer impact (mechanic movement). In these terms only one mechanical quantum is the lost - the tribological (wear) standard. This ideal state of contact of friction (solid) is the state of the dynamic dissipative structure of friction (third body). This is the state of a self-organized nano-quantum solid lubricant.

An oil scoop is a device that is used to capture a jet of oil to lubricate aeroengine bearings where direct oil injection is otherwise not an appropriate or suitable option. The challenge for the oil scoop is to capture the oil jet radially and redirect the oil along the axis of the shaft to be available at the bearings. There are different designs but a typical oil scoop consists of a set of radial scoops in the shape of a prismatic wedge attached to a rotating shaft with the leading edge encountering the oil jet or in some cases jets. The scoops are contained within a cyclindrical enclosure to ensure maxima amount of oil capture. The space below the scoop, and between the shaft, traps the oil as the scoop rotates in a direction against the oil jet thereby getting the oil captured into a pocket along the shaft and the oil is driven to the bearing under the pressure to the bearings. A very high percentage of the oil is lost as the leading edge of the scoop encounters the oil jet. In this work, we are looking at the oil jet encounter with a scoop to understand how to the shape of the scoop affects the jet-edge losses.