循环加热-淬火工艺下超细晶奥氏体的晶粒演变特征  

Evolution of ultra-fine austenite grains in Nb and Nb-V-Ti microalloyed low carbon steel under cyclic heating-quenching treatment

作　　者：姚圣杰[1] 杜林秀[1] 刘相华[1] 王国栋[1] 

机构地区：[1]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110004

出　　处：《材料热处理学报》2009年第5期50-54,共5页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(50527402)

摘　　要：分别利用含Nb钢和Nb-V-Ti钢研究了循环加热-淬火工艺下原始组织分别为温轧铁素体/珠光体、温轧回火马氏体以及常规铁素体/贝氏体的热模拟试样在不同循环次数条件下所获得的超细晶奥氏体晶粒的演变特征。研究表明：复合微合金化更有利于该工艺下奥氏体晶粒的超细化,且相比之下以温轧铁素体/珠光体为原始组织更有利于获得超细晶奥氏体,利用这一原始组织在3-4次循环加热-淬火处理后得到奥氏体晶粒尺寸在1-2μm;同样原始组织条件下,单纯添加Nb使得实现最大程度奥氏体晶粒超细化效果所需要的循环加热-淬火次数减少;根据Nb-V-Ti复合微合金钢中析出相粒子的透射及能谱分析发现,V的大量固溶以及Nb的部分溶解很大程度上决定着微合金元素添加对奥氏体晶粒超细化的影响程度。Effects of initial microstructure（warm-rolled ferrite/pearlite,warm-rolled tempered martensite and ferrite/bainite） and cycle times of repetitive heating-quenching treatment on the evolution of ultra-fine austenite grains in Nb and Nb-V-Ti microalloyed steel were investigated.The results indicate that much more significant refinement of austenite grains can be expected in Nb-V-Ti microalloyed steel by cyclic heating-quenching treatment,and the initial microstructure of warmrolled ferrite/pearlite is favourable for the refining of austenite grains,and from which austenite grains in size of 1～2μm can be obtained for the steel with the repetitive treatment for 3～4 times.Otherwise,less times of repetitive treatment is required to reach the minimum value of austenite grain size for the Nb-steel compared with the Nb-V-Ti microalloyed steel.Effects of the microalloying on ultra-refinement of austenite grains greatly depend on the amount of dissolved vanadium and niobium,according to TEM obser vation and EDS analysis of second-phase particles in Nb-V-Ti steel.

关 键 词：超细晶奥氏体 低碳微合金钢 循环加热-淬火 原始组织 

分 类 号：TG142.33[一般工业技术—材料科学与工程]