Research On The Wear Resistance Of A Low-alloyed Cast Steel

Friction is the root cause of energy consumption and wear is the main reason for the spillage of material. Therefore, the wear resistance of friction pair material is one of the important criteria when selecting materials. There are many factors that influence the wear of friction pair, not only affected by the structure and property of material, but also relate to the speed, load, ambient medium of the friction pair and so on. By adjusting the material composition and process of friction pair, optimized combination of hardness and toughness can be obtained for the most part, thus friction pair with good wear resistance is acquired. At present, low alloy cast steel is widespread used because of its excellent obdurability, but researches on friction pair are relatively less, and its researches are mainly concentrated in the direction of surface coating to improve wear resistance. The research on wear resistance of low-alloy cast steel and its influencing factors is of great significance.In this study, in the purpose of studying wear resistance of low alloy cast steel, low alloy cast steel (quenched and tempered+local quenching) is taken as the ring while different heat treatment of40steel and QT as the shaft, the effect of heat treatment states of40steel and nodular cast iron, rotating speed of wear test on the wear resistance low alloy cast steel by shaft-ring friction method is studied. Each friction pair is conducted rotating speed of120r/min and60r/min, duration is35h of wear test on wear test device which was reformed by the authors. Combined with optical microscope, Rockwell hardness tester, Brinell hardness tester, micro hardness tester, scanning electron microscopy and X-ray diffraction analyzer etc. analysis test equipment, analyze and discuss wear rate and relative wear resistance of the friction pair, and their change, the morphology of grinding crack and abrasive dust, abrasive dust phase analysis.In the friction of40steel and low alloy cast steel, the relative wear resistance of low alloy cast steel shows:with the hardness of shaft reduced and wear test rotating speed decreased, its value is also reduced. In the friction of QT and low alloy cast steel, its relative wear resistance reduces when hardness of shaft increasing, and wear test rotating speed increases.When the rotating speed is120r/min, relative wear resistance of rings compose of friction pair with40steel is higher than that of QT; but when rotating speed is60r/min, relative wear resistance of ring compose friction pair with40steel, on the contrary, is lower than that compose friction with QT.The analysis of grinding crack and abrasive dust after wear test shows that, the wear mechanism is generally abrasive wear and adhesive wear when wear test was light-load and low rotating speed. The X-ray diffraction analysis of abrasive dust shows obvious oxidation wear in the wear process, and the degree of oxidation reduce s with rotating speed reduces.