| The thesis is based on the project of ”The research on electric wheel tipper brake disc abrasion resistance and development of high friction synthetic brake pad coupled with the brake disc”, to provide the basis for developing the best heat treatment process of brake disc and the high friction synthetic brake pad.Firstly, the material of brake disc is determined to be 42 CrMo quenched and tempered steel. In this paper, it was conducted different heat treatments to obtain some samples with different organizations and surface hardness. The braking friction and wear performance was measured when the different heat treatments of brake disc samples were coupled with the original brake disc using MM1000 friction and wear tester and MM3000 friction and wear tester. It shows that: the best heat treatment process of the 42 CrMo brake disc is the 840? quenching and 400?temping. Compared with the normalized brake disc sample, the wearing capacity of the brake disc treated by the process decreases greatly, about 43%; the braking curve is stable, it has good friction and wear properties.Furthermore, the constant speed friction and wear properties of the brake disc samples was measured using MG-2000 pin-on-disc friction and wear testing machine and the wear mechanism of 42 CrMo was discussed. Therefore, the best heat treatment process of the brake disc was determined to realize the high wear resistance and good braking of the brake disc combing with the brake friction and wear test results. It shows that the wearing capacity of the brake disc treated by the process of 840?quenching and 400? temping decreases greatly to 57.8% comparing with the normalized brake disc sample, and it has an appropriate friction coefficient.The wear mechanism of 42 CrMo varies from abrasive wear to adhesive wear along with the contact pressure and speed increase. The wear mechanism of 42 CrMo is mainly abrasive wear when the speed and contact pressure are lower, and the wear mechanism is adhesive wear when the speed and contact pressure are higher, and the time when severe wear is happened at higher speed is shorter than lower speed.Finally, the influence of different ratio of cashew-modified resin to rubber power on the friction and wear properties of synthetic brake pad was studied systematically,and the coupled brake pad has a suitable and stable friction coefficient and the lowest wear volume when the ratio of cashew-modified resin to rubber power is 2:1. Then comparing with the friction and wear properties of the original brake pad, it showsthat, the friction coefficient is basically the same, and the self-made synthetic brake pad has a lower wear rate. |
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