•Dry-ice blasting (DIB) application.•Stripping efficiency of an organic coating (paint)•Erosive wear damage on steel surface.
Dry-ice blasting (DIB) has been widely used in the industry for several ...applications. However, its erosive effect on surfaces has not been studied deeply. This work aims to study the efficiency of DIB for stripping organic coatings (paints) on steel surfaces and its corresponding erosive damage as generated by different jet angles. In addition, the surface cooling during DIB was analyzed to get a deeper understanding of its influence on erosion wear mechanisms. The results have shown that the stripping efficiency increased with the increase of jet impact angle exhibiting minor evidence of surface damage in form of micro craters. In addition, it was observed that surface cooling could be reduced by increasing the initial temperature of the sample and reducing impact angles (i.e., 30°). Finally, it was found that the erosive wear mechanism of DIB is controlled by the ductile–brittle transition of the surface by undercooling caused by DIB.
Rolling contact fatigue (RCF) can damage and reduce the life of the wheel and rail materials due to the degradation of surfaces in contact. The complex combination of RCF with corrosion can also ...contribute to the rapid surface degradation of wheel and rails materials. It is a serious problem when a railway system's environmental conditions can lead to severe corrosion.Even in some cases, severe corrosion caused by rainwater was observed in some open warehouse facilities. This work aims to investigate the influence that corrosion by artificial rainwater has on the generation and propagation of cracks caused by RCF. Twin disk tests were conducted on disk specimens manufactured from wheel and rail sections with corrosion and without corrosion zones on their contact surfaces. Corrosion on the wheel and rail disk specimens was accelerated by the potentiodynamic anodic polarization (PAP) process. The results show that PAP tests can promote pits and micro-cracks formation with different morphologies and sizes in both materials. These surface defects in rail material can grow and accelerate the cracks from the surface and down deep into the subsurface. Finally, pitting and corrosion were removed by the wear action in the wheel material. However, longer and deeper cracks were observed. Results showed that corrosion significantly influences RCF development on rail material.
•Evaluation of corrosion by artificial rainwater on wheel and rail materials.•Corrosion influences on the generation of cracks in rail material by RCF.•Development of a novel method to produce corrosion on twin disk samples.
•Rail and wheel materials from different standards were tested.•Wear maps of different standards were displayed.•In this study, the sliding speed is the most influencing parameter.
Wheel and rail ...materials are exposed to a large number of factors that affect their wear-resistant performance such as, large contact pressures, sliding speeds, high temperatures, material degradation by natural and artificial contaminants, etc. This directly affects the maintenance operations, so, an accurate wear prediction is required. Wear maps are an important tool to predict and identify wear regimes that impact maintenance schedules and consequently cost reduction.
This work aimed to develop wear maps for a 115RE rail material and an ER8 wheel material, which are materials used in railways systems in Mexico, as well as identify the wear regimes and wear mechanisms replicating the wheel-rail interface conditions.
Metallographic analysis and hardness tests were carried out for both materials. Wear tests were carried out by using a pin-on-disk tribometer. The resulting wear maps showed that a catastrophic wear regime occurs at medium sliding speed and low contact pressure values for the wheel. On the other hand, for rail, catastrophic wear regime occurs at high sliding speed and low contact pressure values.
This work aims to determine the alteration of lubricity properties of Jatropha oil (SJO) due to thermal ageing caused by approached long-term use conditions as lubricant in engines. SJO, a mineral ...engine oil (EMO) and a blend made of 80%vol. of EMO and 20%vol. of SJO (B20) were tested. The oils were thermally aged at 160 °C for 30 and 60h. Oil ageing was characterized by measurement of oxidation, depletion of additives, kinematic viscosity and viscosity index. Ball-on-disk tests were conducted to evaluate friction coefficients and wear rates of disks samples from engine cylinder liners by using the oils. SJO was seriously oxidized compared to EMO and B20 by ageing, exhibiting high changes of viscosity from 58.8 to 1970 cSt at 26 °C and decrease of viscosity index from 262 to 200.4. The friction coefficients of SJO were not altered remaining in low values 0.06–0.07. The viscosity increase allowed a reduction of wear rates from 0.00065 to 0.0002 mm3/m. B20 exhibited better lubricity properties than EMO; and they even were improved after ageing. Thus, SJO could be blended with mineral oils in low concentrations to reduce friction and wear while promoting safe use of a renewable product in short and long-term uses in engines.
•Oxidation and lubricity of Jatropha oil due to thermal ageing was assessed.•Jatropha oil was seriously oxidized by thermal ageing.•Viscosity of Jatropha oil was highly raised by thermal ageing.•Friction coefficient of Jatropha oil was not altered by thermal ageing.•Wear produced by using Jatropha oil was reduced due to thermal ageing.
