低合金耐磨钢回火过程中的碳化物析出  

Carbide precipitation during tempering of low alloy wear resistant steel

作　　者：曹艺 王昭东[2] 邓想涛[2] 朱万军[1] 陈韧[1] CAO Yi;WANG Zhao-dong;DENG Xiang-tao;ZHU Wan-jun;CHEN Ren(Liaoning Key Laboratory of Optimization and Utilization of Non-associated Low-grade Iron Ore in Benxi, Liaoning Institute of Science and Technology, Benxi 117004, China;State Key Laboratory of Roiling and Automation, Northeastern University, Shenyang 110819, China)

机构地区：[1]辽宁科技学院辽宁省本溪低品位非伴生铁矿优化应用重点实验室,辽宁本溪117004 [2]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819

出　　处：《材料热处理学报》2018年第4期113-120,共8页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51774074);辽宁省教育厅项目(L2015268);辽宁科技学院博士启动基金(1406B07)

摘　　要：将低合金耐磨钢淬火样品在200~600℃进行不同温度回火,采用透射电镜（TEM）和电子探针分析仪（EPMA）研究淬火与回火样品中碳的偏聚与碳化物析出特征。结果表明：碳的偏聚位置和碳化物形态、大小、类型及分布情况在不同样品中存在差异;淬火马氏体板条间存在宽为20~60 nm的残留奥氏体薄膜,250℃回火时开始在原位置分解成连续分布的碳化物;淬火样品中碳在非晶界位置发生轻微偏聚,回火温度升高后易向晶界及其它界面附近偏聚;200℃回火样品中发现细片状或条状ε碳化物,宽10~20 nm,长80~150 nm,在300℃回火后被θ渗碳体代替;350℃以上,碳化物逐渐粗化成为棒状或球状,500~600℃回火后球状碳化物逐步占主导地位。此外,马氏体板条局部存在少量相变孪晶。The characteristics of carbon segregation and carbide precipitation in low alloy wear resistant steel after quenching at 910 ℃ and tempering at 200-600 ℃ were studied by means of transmission electron microscopy and electrical probe microanalysis. The results show that the segregation position of carbon and the morphology,size,type and distribution of carbide in different specimens are different.There is a retained austenite film with a width of 20-60 nm between martensitic lath in as-quenched specimen. When tempering at 250 ℃,it begins to decompose into carbides with a continuous distribution at the original position. The carbon in the quenched sample has slight segregation at the position of the amorphous boundary,and with the increasing of tempering temperature,the segregation of the carbon in the quenched sample is easy to occur near the grain boundary and other interfaces. The fine plate-like and/or strip-like ε-carbide with 10-20 nm in width and 80-150 nm in length in the matrix is observed when tempering at 200 ℃,and is replaced by θ-cementite when tempering at 300 ℃. After tempering at above 350 ℃,the carbide gradually becomes rod-shaped or spherical,and the spherical carbides dominate gradually after tempering at 500-600 ℃. In addition,there is a small amount of phase change twin in part of the martensite lath.

关 键 词：耐磨钢 碳化物 回火 板条马氏体 

分 类 号：TG142.72[一般工业技术—材料科学与工程]