锰钒高铬铸铁的深冷硬化行为及机理研究  

Hardening behavior and mechanism for MnV high chromium cast iron subjected to cryogenic treatment

作　　者：刘浩怀[1] 张建华[1] 许庆陵[1] 

机构地区：[1]广州大学化学化工学院/分析测试中心,广东广州510006

出　　处：《广州大学学报（自然科学版）》2011年第6期29-33,共5页Journal of Guangzhou University:Natural Science Edition

基　　金：国家自然科学基金项目(50901047);教育部博士点新教师基金项目(200806101051);广东省自然科学基金项目(52011040004038);广东省教育厅育苗项目资助

摘　　要：采用X射线衍射、金相分析、硬度测定等方法研究了锰钒高铬铸铁经深冷处理后的硬化行为和硬化机理.结果表明,锰钒高铬铸铁在亚临界处理(400～650℃)后再深冷处理的过程中,硬度先升高后下降,其整体硬度显著高于未经深冷处理的试样.显微组织分析表明,深冷处理使锰钒高铬铸铁的残余奥氏体含量下降,马氏体含量增多,同时析出了大量的细微碳化物,并且深冷处理过程中析出的二次碳化物较空冷时多.大量马氏体的形成和微小二次碳化物的析出强化作用显著提高了锰钒高铬铸铁的硬度,当基体内残留15%～20%的残余奥氏体时其硬度达到最高.The hardening behavior and hardening mechanism of MnV high chromium cast iron subjected to cryogenic treatment were investigated by X ray diffraction, metallographic analysis and hardness test in this paper. The results show that the hardness of the alloy increases until it reaches the maximum, and then begins to fall by the sub-critical treatment （ from 400 ℃ to 650 ℃ ） followed with cryogenic treatment, and its hardness is higher than that of air cooling. The analysis of microstructure reveals the retained austenite content of sample lessens greatly after cryogenics treatment, and the amount of precipitated secondary carbides was more than that in air cooling. The hardness of MnV high chromium cast iron can be improved obviously due to the precipitation of carbides and the martensite transformation resulting from cryogenics treatment. When there was about 15% 20% retained austenite in the matrix, its hardness reaches the maximum.

关 键 词：硬化机理 深冷处理 高铬铸铁 亚临界处理 

分 类 号：TG156.9[金属学及工艺—热处理]