The Studay Of Rolling Contact Fatigue Failure And Tests On Super Hard Coating Parts

With the developments of materials science and coatings technology, coating technology in super hard materials is used to improve surface mechanical functions and friction properties of accessories. It is one of the principle research aspects of the surface engineering field. But the study on the rolling contact fatigue (RCF) mechanism of super hard material coatings is still in grope. Therefore, the study of influencing factors on the RCF of super hard material coatings not only has an important practical significance,but also can provide some scientific references necessarily to the exploitation and applications of the super hard material coatings technology.This certification sums up many different factors which may have an impact on the RCF life of super hard coatings material's parts. Meanwhile, by using Large-scale finite element software ANSYS as an analytical tool, taking one spherical contact as a model resorting to numerical simulation technique and aiming at typical coatings material, we analyze the influence of coating properties (elastic modulus, coating thickness) and the load change to the rolling contact stress field.Scientific analysis tells us that the largest shear stress is the fundamental reason which causes the RCF of the super hard material coatings. At the same time, coatings productive technology and performance parameter are also the important factors that affect the RCF of the super hard material coatings. With the increase in coating materials'thickness and Young's modulus, below surface's largest equivalent stress and shear stress gradually become large, but the growth has a big difference. Furthermore, according to the result of numerical modeling, there is an obvious regularity from the change of external applied load to the largest shear stress and the largest equivalent stress. This provides a useful reference to elastic stress field's formula of super hard coatings material. In addition, this dissertation resorts to new RCF testing machine of super hard coating materials, takes super hard coatings'axial contact bearing as an example, does a large number of RCF life tests, applies optical microscope and scanning electron microscopy techniques, and finally analyzes RCF acts of super hard coating material.Many tests tells us that the lifespan of the super hard coating part RCF are affected by coatings'thickness and hardness Besides, we put hard particle in lubricants when doing the accelerated fatigue experiment, and then analyze fatigue acts and accelerated mechanics.All the above work is very significant to the further study of super hard coatings material's RCF mechanics and assessment technology.