Study On Tribological Properties Of Steel-copper Couples In Oxidizing And Damp-heat Atmosphere

With the development of technology and the progress of industry, the tribological problems under harsh working conditions become more and more serious. Especially, the tribological problems in special atmosphere are involved with tribology, materialogy, physicochemistry, heat transfer, and many other cutting-edge interdisciplinary frontier research fields. It is also an essential common technical challenge that restricts the development of many important fieds, such as aerospace, military equipment, high-speed transportation and so on. Based on tribological properties in oxidizing and damp-heat atmosphere, the tribological properties of steel/brass couple with different thermophysical properties were investigated in different atmosphere environment by using QG-700 pin-on-disk high temperature and atmosphere tribo-tester. The morphologies, microstructures and the chemical elements of pin, disk and wear debris were analysised with the help of SEM, three dimension profile tester, EDS and XRD. From the views of synergistic effect of thermal, chemical and mechanical, this paper analyzed the effects of environmental atmospherere on tribological properties and wear mechanisms. The main contents are as following:A humidity control divice was designed, installed and debugged independently. This device solved the problem of humidity control in semi-closed circumstance. What is more, it meeted the requirements on fast humidity adjustment, high control precision and wide humidity range requirement. During the experiments, this guaranteed the smooth process of experiment.By tribological performances testing in different humidities of air and oxygen atmospheres, the tribological properties and wear mechnisms rules changing with the increase of relative humidity were studied. The tests found that different characteristics of surface films on pins were the main reason for the difference of tribological property in air and oxygen. Based on the analysis, the application requirements of CrNiMo steel/brass frictional couple in special atmosphere environment were proposed.Based on the experimental study of the tribology properties in environmental temperature range from 25℃to 225℃, the rules of tribological properties was changing with the increasing of temperature were disscussed. Combining the micro- analysis, the wear mechnism was discussed. Based on such results, the optimum environment temperature conditions were determined for wear mechanism transition. Finally, the best environmental temperature application condition for the frictional couple was proposed.The distributions of the friction temperature and contact pressure in contact area of the couple under combined effect of mechanical and thermal load during sliding friction process were studied by nonlinear finite element analysis. The results showed that the accuracy and effectiveness of the numerical simulation method could satisfy the requirement of the test and can achieve the desired targets. These simulated results provide the theoretical basis for the transition of the wear mechanisms.