Study On RCF Particle Accelerated Test And The Mechanism Of RCF Particle Accelerated Test On Supperhard Coating Suface

With the developments of materials science and surface engineering technology, the superhard coating has become one of the effective ways to improve the mechanical properties and tribological properties of parts. Study on the rolling contact fatigue (RCF) mechanism of superhard material coatings is still in grope. Research about superhard coating fatigue mechanism and evaluate method can provide scientific reference for the development and application of coating technology.Low load, high speed cycle, the traditional test methods are long bearing life, high cost and poor reliability of test results. In this regard, Under the premise of maintaining bearing in contact fatigue failure mechanisms constant, the accelerated life test methods have become the research hotspot. Professor Yang Yu lin design a new type of contact fatigue test machine (RCFYSU-1 test machine) and put forward a new accelerated fatigue testing method which is adding hard particles to the oil to research and evaluate the super-hard coating for bearing rolling contact fatigue life.This paper summarizes the RCF life of superhard coatings parts of various factors, and application of finite element software ANSYS as an analytical tool , ball-surface contact containing a single particle as a model, for a typical coating layer material analyzed the influence of coating thickness, particle size for rolling contact stress. Results showed that: the existence of particles can cause stress concentration on the coating surface and the faying surface and will cause plastic deformation defect on the surface. We carry on the contact fatigue experiment of coated bearing and plain bearing adopting the accelerated fatigue testing method and the conventional fatigue testing method on RCFYSU-1 test machine. Test results show that the new accelerated test method does not change the bearing contact fatigue failure mechanisms, and achieve speed up of about 3. In order to further validate the accelerated fatigue mechanism, We prefabricate defect on bearing surface to carry on the contact fatigue experiment, observe and analyse fatigue crack formation and growth process, the results show that: the initial fatigue crack appear in a very short period of time around the export of defect. Prefab surface defects curtail the fatigue life of bearings.All the above work is significant to the further study on the mechanism and application of the estimate method of supper hard coating part RCF life .