The Effect Of Friction Components On Friction Performance Of Deep-Drilling Brake Linings Material

Comparing to the conventional geological drilling,Deep-drilling rig has got a significant promotion in so many aspects such as machine power,lifting load and speed,which is requiring a further research on the safety and reliability of the rig brake system.The disc brake,that replacing belt brake as a major form of rig brake system,exhibits a remarkable strengthening on the load amount and has develops a sieries of new functions,so it is necessary to put on a study on the selection and optimization of the friction materials for brake linings.According to the earlier research,bronze-based brake linings in powder metallurgy,which has proved a outstanding property on thermal conductivity and oxide etch resistance,greatly meets the needs of the deep-drilling disc brake system.Usurally we put a certain sort of powder which is extremely hard into the bronze-based alloy in order to get a promotion on material's friction performance.In this study we selected the high chromium cast iron,Al₂O₃,SiO₂,WC,SiC as five representatives of commonly-used grinding material to conduct our test.After the designing of the formula,mould along with the sintering process,we finally got five groups of samples of the brake lining material containing different friction components.Through the data from the friction,wear and mechanical test,these conclusions can be drawn:1.The high chromium cast iron,worked as a friction component in the alloy,exhibited a good bonding with the base?lowest porosity of all groups?;2.The samples which containing Al₂O₃ and SiC showed a poor wettability of bronze under the same sintering process.3.The hardness and strength of brake linings depended largely on the material and structure of the base.However after adding different friction components,these two index changed relatively.In our test when the adding amount of the friction component were 8%,the sample containing Al₂O₃ presented the hardest one,while SiO₂ ranked the last place in Brinell Hardness.The sample containing WC and Al₂O₃got the first and last place in strength.4.The friction coefficient raised obviously since the friction component grew harder under the condition of low temperature and low speed.The highest friction coefficient was obtained in the sample containing Al₂O₃,while adding SiO₂ contributed the least in fricion among all groups.5.The best wear behavior under both high-speed and low-speed condition was found in the samples containing high chromium cast iron,while adding Al₂O₃ and WC as friction components decreased the alloy's wear resistants.6.High chromium cast iron can be a great reinforcement in deep-drilling brake linings of bronze-based powder metallurgy material potentially referring the results we obtained from the friction test.