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本文阐述了石油牙轮钻头牙爪用SAE 8720渗碳钢深冷处理及磨损试验的试验方法,对比分析了SAE8720钢渗碳及渗碳后深冷处理的硬度与耐磨性。用大视场显微镜分析了深冷处理对SAE 8720渗碳钢金相组织的影响,用X射线衍射法对表层残余奥氏体作了定量分析,并分析了残余奥氏体对硬度及耐磨性的影响。结果表明,深冷处理可促使残余奥氏体向马氏体转变,淬火马氏体回火后可析出高度弥散的超微细碳化物,其残余奥氏体量由56％降为20.05％,硬度提高3.3 HRC,耐磨性提高156％。
In this paper, the test methods of cryogenic treatment and wear test of SAE 8720 carburized steel for claw of petroleum roller cone bit are described. The hardness and wear resistance of SAE8720 steel after carburizing and carburizing are compared. The effect of cryogenic treatment on the microstructure of SAE 8720 carburized steel was analyzed with a large field microscope. The residual austenite in surface layer was quantitatively analyzed by X-ray diffraction. The effect of retained austenite on hardness and wear resistance Impact. The results show that the cryogenic treatment can promote the transformation of retained austenite into martensite. After quenching martensite tempering, highly dispersed ultrafine carbides can be precipitated, the retained austenite content decreases from 56% to 20.05%, and the hardness increases 3.3 HRC, wear resistance increased by 156%.