【作者】 计云萍； 任慧平； 侯敬超； 瞿伟； 靳晓艳； 宋艳青；

【Author】 JI Yunping;REN Huiping;HOU Jingchao;QU Wei;JIN Xiaoyan;SONG Yanqing;School of Materials Science and Engineering,Shanghai University;School of Material and Metallurgy,Inner Mongolia University of Science and Technology;Key Laboratory of Integrated Exploitation ofBayan Obo Multi-Metal Resources;

【机构】 上海大学材料科学与工程学院； 内蒙古科技大学材料与冶金学院； 内蒙古自治区白云鄂博矿多金属资源综合利用重点实验室；

【摘要】 20MnCrNi2Mo耐磨铸钢铸态组织以粒状贝氏体为主,将其铸态组织分别加热到200⁶50℃并保温1 h进行回火处理,采用QUANTA400环境扫描电镜和JEM-2100F透射电镜观察回火过程中的显微组织,采用电解萃取并结合X射线衍射的方法对回火过程中的析出相进行定性及定量分析,采用D8 ADVANCE X射线衍射仪对不同温度回火后残留奥氏体量进行定量测定,分析20MnCrNi2Mo低合金贝氏体耐磨铸钢回火过程中的组织转变。结果表明,20MnCrNi2Mo低合金贝氏体耐磨铸钢200⁶50℃保温1 h回火过程中析出的碳化物为M₃C型,随着回火温度升高,合金元素向Fe₃C扩散富集形成合金渗碳体;500℃回火时观察到贝氏体铁素体条合并、形成边界模糊的亚晶,650℃回火时亚晶变得清晰;200℃回火时M/A岛基本未发生分解,随回火温度的升高,M/A岛逐渐发生分解,到450℃回火时,M/A岛明显减少,已检测不到奥氏体的衍射峰。更多还原

【Abstract】 The cast microstructure of the wear- resistant cast steel of 20MnCrNi2 Mo mainly consists of massive granular bainite.The cast samples were tempered at 200℃,250℃,300℃,350℃,400℃,450℃,500℃,550℃,600℃ and 650℃ respectively for 1 h.The microstructure was observed by QUANTA-400 environmental scanning electron microscope and JEM-2100 transmission electron microscope,the precipitation was qualitatively and quantitatively analyzed by the method of electrochemical extraction combined with X- ray scattering techniques,and the retained austenite after different temperature tempering was measured quantitatively by D8 ADVANCE X ray diffracmeter.The microstructure transformation of the low- alloy bainitic wear- resistant cast steel of 20MnCrNi2 Mo during the tempering was investigated.The results show that the precipitated carbide during the tempering from 200℃ to 650℃ for 1h is M₃C.With the tempering temperature increasing,the alloying elements will diffuse and gather to Fe₃C and.then form,alloying cementite.The combination,of bainite ferrite strips and the formation of the subgrains with vague boundaries are observed when tempering at 500℃,and the subgrains are found becoming distinct when tempering at 650℃.The M/A islands do not decompose tempered at 200℃ by and large,with the increase of the tempering temperature,the M/A islands gradually decompose,and the amount of the M/A islands decreases so obviously that it can not be detected when the tempering temperature is up to 450℃.更多还原