低碳合金钢表面硬贝氏体的制备及其组织特征  

Preparation and microstructural characterization of hard bainite in surface layer of low-carbon alloy steel

作　　者：张朋[1] 张福成[1] 王天生[1] 郑春雷[1] 韩波[1] 吕博[1] 郑炀曾[1] 

机构地区：[1]燕山大学亚稳材料制备技术与科学国家重点实验室,河北秦皇岛066004

出　　处：《材料热处理学报》2009年第4期44-47,共4页Transactions of Materials and Heat Treatment

基　　金：新世纪优秀人才基金(NCEF-05-0260);国家自然科学基金(50671091);河北省自然科学基金(2006000217;2006001026)

摘　　要：研究了19Mn2Cr2NiMoAl低碳合金钢表面获得硬贝氏体组织的热处理工艺及其组织结构特征。利用自行设计的滴注式可控气氛全自动渗碳炉渗碳,然后将试样加热进行奥氏体化处理,并直接淬入盐浴中,保温不同时间进行等温淬火。利用光学显微镜、透射电镜以及显微硬度计对热处理后19Mn2Cr2NiMoAl钢渗碳层的组织和硬度进行分析研究。结果表明,该钢经过230℃保温48h等温淬火后获得最佳的组织结构,其组织特征是,表层是平均尺寸约为80nm的贝氏体铁素体层片,片间为平均厚度为十几纳米的残余奥氏体膜组织;过渡层是硬贝氏体和低碳马氏体的混合组织;心部是低碳马氏体组织。由此获得的试样的表层硬度达到620HV,而心部的硬度为460HV。A heat treatment technology was proposed for obtaining hard bainite in the surface layer of low-carbon alloy steel.In this process,the sample of 19Mn2Cr2NiMoAl steel was carburized using an instillation-style atmosphere-controllable carburization furnace,and then reheated for austenization and quenched into salt bath for different time.The microstructure of the carburized layer was studied by optical microscopy and transmission electron microscopy,and the hardness distribution along the depth of carburized layer was measured. The results show that nanoscale bainitic mierostructure composed of lathy bainitic frnite with about 80 nm thickness and retained austenite films with over 10 nm thickness between bainitic ferritic laths can be achieved in the carburized layer by austempering at 230~C for 48h. The lath martensite is formed in the center of the sample, and the mixture of nanoscale bainite and lath martensite is obtained in transition layer. The hardness of surface and center of the sample is 620HV and 460HV, respectively.

关 键 词：低碳合金钢 渗碳 等温淬火 硬贝氏体 

分 类 号：TG142.1[一般工业技术—材料科学与工程]