| In this paper, HSS(high speed steels) drill W9Mo3Cr4V, W6Mo5Cr4V2 and W4Mo3Cr4VSi were treated in the ultra-low temperature equipment;wear resistance ,hardness ,roughness of the cryogenic treated and cryogenic untreated drills were compared in the same metal-cutting conditions. The wear resistance, flank morphology, as well as changes in the microstructure of drills were researched before and after cryogenic treatment.The results show that, after cryogenic treatment, W9Mo3Cr4V increased in the hardness of 0.5-1.8, W6Mo5Cr4V2 increased in the hardness of 1.4, W4Mo3Cr4VSi increased in the hardness of 1.0-1.3; surface roughness reduction of W6Mo5Cr4V2 was 0.04-0.11, surface roughness reduction of W4Mo3Cr4VSi was 0.2 to 0.6 ; in the same cutting process, after the cryogenic treatment the tool wear resistance increased, and to map out the different specifications of W9Mo3Cr4V, W6Mo5Cr4V2 and W4Mo3Cr4VSi ; before and after the deep cold treatment, the wear curve through the right flank morphology was observed .The results show that after the cryogenic treatment ,the flank wear was obviously lighter than the untreated tools. By the use of scanning electron microscope ,the author observed the changes in the microstructure before and after the deep cold treatment, the results showed that the cryogenic sample precipitated a large number of carbide Particles.Cryogenic treatment can change the micro-structure of tool material, enhance wear-resistant of the tool materials, to a certain extent, improve the tool material's hardness, and reduce the surface roughness. Cryogenic treatment made a part of residual austenite become martensite, and precipitated a large number of carbide particles, the diffusion of small carbide precipitation particles can increase wear-resistant ability, but also increase the hardness of high-speed steel, so cryogenic treatment can improve the wear resistance of high-speed steel drill bit. and extend the life of the tool. |
PDF Full Text Request