Study On Micro-damage Of Ground Surface And Its Effect On The Tribological Properties

The properties of the using machines, especially reliability and service life, have a close relationship with the surface processing of machine parts. Micro-damage of the part surface is an important indicator to determine the quality of parts processing, which directly impacts on the fatigue strength of parts, tensile strength, surface hardness and wear resistance, thereby affects the performance of parts.At present, studying the problem of micro-structural damage mainly comes from three aspects, which the experimental study, theoretical study and numerical simulation. Grinding damage can be researched on from the residual stress of grinding cracks, grinding streaks, grinding burn and can also be analyzed from the influence of grinding surface damage on the performance of parts. Using45steel as grinding experimental material, through the micro-surface map of testing parts observed via the scanning electronic microscope under different grinding conditions, thesis speculates the causes of the micro damage and comes up with some preventive measures. Then thesis acquires the tribological factors through the experiment, comprehensively analyzes and judges the influence of micro damage of part surface on tribological properties. The main work and the results are as below:(1) By means of finite element analysis, thesis analyzes the influence of different grinding conditions (such as grinding depth and grinding feed amount) on grinding residual stress of45steel through the ANSYS finite element analysis software, acquires the data and distributing contours of residual stress.(2) Thesis deals with defects of surface grinding, analyzes the causes and preventive measures. Based on the contours of stress distributing, thesis predicts and judges the distribution of grinding cracks.(3) Thesis does surface grinding experiment with45steel under different grinding conditions, acquires the testing parts by means of dry grinding, wet grinding and changing grinding depth. And then, through the observation via scanning electron microscope, thesis analyzes studies and discusses different grinding damages. (4) Based on the testing parts in the previous experiment, thesis acquires friction coefficient under the different loading conditions. Then combining with the SEM diagram of testing parts, thesis analyzes and discusses the influence of surface micro-damage on tribological properties, acquires the conclusions of the experiment.The subject of this thesis combines with the theory of surface grinding micro-damage, analyzes and discusses the factors on surface grinding micro-damage. At the same time, this thesis also does the experiment test the tribological factors of the testing parts, verify its correctness and also these experimental parts,studies the relationship between surface micro-damage and tribological properties preliminarily.