Evaluation of the strength anisotropy for railway wheels

The results of experimental investigation of railway wheel failures and strength anisotropy due to rolling contact fatigue are presented. The results indicate that plasticity acts to concentrate regions of intense hardening near the edges of contact. The determination of overall mechanical properties of small-scale volumes frequently relies on the indentation technique. Strength characteristics of the wheel material were investigated by dynamic indentation method and portable dynamic indentation tester was used for hardness measurements. It was found that some characteristic force values of the instrumented hardness test are very well correlated to tensile strengt

Evaluation of the strength anisotropy for railway wheels

The results of experimental investigation of railway wheel failures and strength anisotropy due to rolling contact fatigue are presented. The results indicate that plasticity acts to concentrate regions of intense hardening near the edges of contact. The determination of overall mechanical properties of small-scale volumes frequently relies on the indentation technique. Strength characteristics of the wheel material were investigated by dynamic indentation method and portable dynamic indentation tester was used for hardness measurements. It was found that some characteristic force values of the instrumented hardness test are very well correlated to tensile strengt

Evaluation of the strength anisotropy for railway wheels

The results of experimental investigation of railway wheel failures and strength anisotropy due to rolling contact fatigue are presented. The results indicate that plasticity acts to concentrate regions of intense hardening near the edges of contact. The determination of overall mechanical properties of small-scale volumes frequently relies on the indentation technique. Strength characteristics of the wheel material were investigated by dynamic indentation method and portable dynamic indentation tester was used for hardness measurements. It was found that some characteristic force values of the instrumented hardness test are very well correlated to tensile strengt

Influence of copper coatings formation methods on tribological properties of friction couples

2-s2.0-84905833741 - ScopusIn this study, the tribological behavior of copper coatings was investigated on 100Cr6 AISI 52100 steel substrates. Electrospark (ESA) and electric conductor explosion (ECE) techniques was employed on substrate with the deposition of copper and bronze powder. Friction tests were made by tribomachine TRM 500 using a friction couple “ball-three plates”. The microstructure of coatings was investigated by means of an optical microscopy and microhardness measurement. In addition, scanning electron microscopy (SEM) and X-ray diffraction meter (XRD) of the used powder and coatings was utilized. The results showed, that Cu coatings induces a large improvement of friction coefficient and, more generally, of all the wear characteristics. The Xrays diffraction studies have not shown the appearance of a new secondary phase, they only relieved internal stresses and lattice defects in the superficial layer. Metallographic analysis showed metallurgically bonded ESA and ECE coatings with no interconnected porosity and microcracking through the coating to the substrate. Microhardness measurements indicate uniformity in microhardness across the coating as well as within the 100Cr6 AISI 52100 substrate substantiating the premise that the ECA and ECE processes does not alter the microstructure of the base materialVytauto Didžiojo universitetasŽemės ūkio akademij

Cracking behavior of electrodeposited nanocrystalline tungsten-cobalt and tungsten-iron coatings

The use of micrometer thick coatings in tribosystems now is of increasing interest in the area of mechanical engineering to reduce friction and wear. This work was initiated to analyse critically the deformation of electrodeposited Co-W and Fe-W coatings resulting from indentation tests, and to identify the microscopic features of the surfaces of such electrodeposited layers. On other hand, the present work focuses on an improved understanding of the plastic deformation field of the indentation made in thin layer deposited on a substrate, especially the mechanisms formation of the pile-ups around the indenter.status: publishe