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The low‐ and medium‐speed diesel engine design changes that have taken place to date, and are predicted to continue for the foreseeable future, present the marine diesel lubricant with a difficult environment which is expected to become more severe with respect to both wear and cleanliness performance, on account of increasing specific power output and wider use of lower grade residual fuels. This article describes in some detail the main in‐house laboratory rig and engine techniques and procedures which have been developed by the Authors' company for assessing the important aspect of wear control; it highlights the special techniques used during shipboard testing for determining cylinder liner and piston ring wear and shows that the results from field testing correlate with those obtained from the in‐house tests used to develop the latest generation of superior quality marine diesel lubricants.

Attempts to reveal some of the factors that might cause measurement and evaluation errors in dry sliding. Discusses matters such us “what” and “how” is simulated and “why” and “what” is really measured and suggests ways to tackle these matters. Presents means of avoiding measurement errors as well as suitable testing procedures. Suggests a strategy of experimental work that encompasses the needs of both pure research and engineering design. It was found that the pin‐on‐disc test largely satisfies the conditions for a good simulation of certain engineering applications while providing a wealth of data for both scientific insight and engineering design.

Economic pressures are driving fleets to substantially increase their maintenance intervals. To meet this challenge, both the original equipment manufacturers (OEM) and the lubricant suppliers have developed new and better products to give users the benefits of extended service intervals while at the same time maintaining equipment life and reducing operating costs. This paper will examine the options available in formulating extended drain transmission and axle lubricants by comparing four products designed to meet the OEM extended service interval requirements. Bench test and field test data will be reviewed which show that by optimizing the base oil as well as the additive system, both synthetic as well as properly formulated mineral oil products can give excellent extended drain performance. With mounting economic pressures in the trucking industry, these new products will give maintenance personnel additional product choices as they move their fleets to extended drain transmission and axle lubricants in an effort to safely extend equipment life and reduce total maintenance costs.

This paper aims to study microstructure and high temperature tribological performance of hypo-eutectic CoCrWC hardfacing alloy (Stellite 12) deposited on steel substrate by plasma-transferred arc (PTA) welding technique.

Microstructural characterization of the deposited coating was made using electron probe microanalysis, X-ray diffraction and microhardness tester. Dry sliding wear tests were carried out with a ball-on-disc type tribometer at room and elevated temperature. Worn surfaces of the samples were examined by the EDX equipped SEM and Raman spectroscopy.

Results revealed that at room temperature and 300°C plasticity dominated wear mechanism was operative. Under oxidation dominated wear conditions (400, 500, 600 and 700°C), testing temperature plays a crucial role on the characteristics of the oxide tribolayers formed on worn surfaces. Development of Cr2O3 in the tribolayer at 600 and 700°C was beneficial in increasing wear resistance of examined coating.

While the sliding wear performance of Stellite alloys at room temperature has been investigated in details, published studies on tribological behavior of Stellite alloys with varying temperature are scarce. Therefore, the present work was undertaken to study the wear mechanisms and the type of tribolayers formed during sliding wear of PTA welding deposited hypo-eutectic Stellite 12 coating with increasing temperature up to 700°C.

This paper aims to investigate the wear behaviour of different materials for cylinder liners and piston rings in a linear reciprocating tribometer with special focus on the wear of the cylinder liner in the boundary lubrication regime.

Conventional nitrided steel, as well as diamond-like carbon and chromium nitride-coated piston rings, were tested against cast iron, AlSi and Fe-coated AlSi cylinder liners. The experiments were carried out with samples produced from original engine parts to have the original surface topography available. Radioactive tracer isotopes were used to measure cylinder liner wear continuously, enabling separation of running-in and steady-state wear.

A ranking of the material pairings with respect to wear behaviour of the cylinder liner was found. Post-test inspection of the cylinder samples by scanning electron microscopy (SEM) revealed differences in the wear mechanisms for the different material combinations. The results show that the running-in and steady-state wear of the liners can be reduced by choosing the appropriate material for the piston ring.

The use of original engine parts in a closely controlled tribometer environment under realistic loading conditions, in conjunction with continuous and highly sensitive wear measurement methods and a detailed SEM analysis of the wear mechanisms, forms an intermediate step between engine testing and laboratory environment testing.

The purpose of this study was to investigate wear behaviours of brake pads produced from carbon–carbon (C/C) composites in both wet and dry friction sliding conditions. Carbon is probably the most remarkable element in science and also C/C composites are a family of advanced composite materials. They are the most advanced form of carbon and consist of fibre based on carbon precursors embedded in a carbon matrix. In the present work, wear test specimens were prepared according to the related standards and they were exposed to pin-on-disc wear testing in wet and dry sliding conditions with different loads as 10, 20, 30 and 40 N with 1 m/s constant sliding speed. Wet friction process was conducted on all specimens by means of rain water collected from the nature.

Pin-on-disc wear test tribology lubrication was used.

Mechanical and physical property measurements of C/C composite brake pad materials: hardness, modulus of elasticity, density and water absorption capacity. Wear performance of materials were measured as coefficient of friction, volumetric loss and specific wear rate.

C/C composite brake pads are used in railway vehicles. Wear performances of them are very important for safety. In this study, wear behaviours of these materials were investigated not only in dry sliding friction condition but also in wet sliding one. Because safety braking is important in all weather conditions for trains, and we used natural rain water to observe the wet sliding friction behaviour of brake pads. “Water lubrication” is an important aspect mentioned in tribology handbooks.

The purpose of this paper is to understand the influence of reinforced fiber length over material‐plastic energy of deformation, clogging, crystallinity, and correlates with the friction and wear behavior of polypropylene (PP) composites under multi‐pass abrasive condition. Also to identify wear mechanisms of glass fiber reinforced PP materials under various abrasive grit sizes and normal loads.

Multi‐pass abrasive wear tests were performed for unreinforced, short, and long glass fiber reinforced PP (LFPP) on a pin on disc machine under three different normal loads and two different abrasive grit sizes for a constant sliding velocity. Measured wear volume was correlated with the plastic energy of deformation by carrying out a constant load indentation test using servo hydraulic fatigue test system. Clogging behavior of test materials was examined with the aid of online wear measurement and wear morphology. Test materials crystallinity was estimated with the aid of X‐ray diffraction investigation and correlated with abrasive wear performance.

Fiber reinforcement in a PP material is found to improve the plastic deformation energy and crystallinity which results in improved abrasive resistance of the material. Increase in reinforced fiber length is found to improve the material cohesive energy and hence the wear resistance. Reinforcement is found to alter the material clogging behavior under multi‐pass condition. Fiber reinforcement is found to reduce the material coefficient of friction, and increase in reinforced fiber length further reduces the frictional coefficient.

Friction wear tests using pin on disc equipment is carried out in the present investigation. However, in practice, part geometry may not be always equivalent to simple pin on disc configuration.

The paper's investigation results could help to improve the utilization of LFPP material in many structural applications.

Influence of reinforced fiber length over multi‐pass abrasive wear performance of thermoplastic material, and online wear measurement to substantiate clogging behavior is unique in the present multi‐pass abrasive investigation.

The aim of this study is to calculate the coefficient of friction of wheel/rail interface in both water lubrication and dry friction conditions.

Specimens taken from wheel and rail used in railway transport were exposed to pin‐on‐disc wear testing with 10, 20, 30 and 40 N loads. The disc took the place of the rail and the pin that of the wheel in wear tests, and rain water was fed to the disc/pin interface with a three drops/min speed in wet friction conditions. The coefficient of friction and weight loss values of specimens were determined and types of wear mechanism were characterized.

It was observed that the friction coefficient decreased in wet sliding experiments, so smaller values were calculated in wet friction conditions than those of dry friction conditions for wheel specimens. However, this decrease was more drastic for rail specimens. Weight and volumetric loss values of rail materials were lower than those of wheel samples.

This study investigates the wet and dry sliding wear characteristics of train wheel‐rail materials.

The purpose of the study is to examine the sliding wear performance of plasma transfer arc (PTA) deposited and laser surface melted (LSM) Mo modified Stellite 12 hardfacings under high contact stresses (i.e. >20 GPa).

For this purpose, after structural characterization, sliding wear tests have been conducted using sphero-conical diamond indenter as the counterface with different normal loads. The wear tracks formed on the hardfacings were examined by atomic force microscopy and scanning electron microscopy.

Both hardfacings showed severe wear (at high contact stress levels ranging from 24 to 41 GPa), which progressed by plastic deformation, although the wear resistance of LSMed hardfacings was better than the PTA hardfacings by a factor of two due to its near surface microstructure characterized as carbide-rich zone.

Sliding wear characterization of a promising 10 Wt.% Mo modified version of commercial Stellite 12 hardfacings (as reported previously by authors) was done in as PTA and LSMed states using nanomechanical test system. To the best of authors’ knowledge, no report is available in the open literature on such hardfacings under these testing conditions.