循环加热_淬火工艺下超细晶奥氏体的晶粒演变特征.docx

第30卷第5期2009年1 0月材料热处理学报TRANSACTIONS OF MATERIALS AND HEAT TREATMENTVol . 30No .5October2009循环加热2淬火工艺下超细晶奥氏体的晶粒演变特征姚圣杰,杜林秀,刘相华,王国栋(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)摘 要:分别利用含Nb钢和Nb2V2Ti钢研究了循环加热2淬火工艺下原始组织分别为温轧铁素体Π珠光体、温轧回火马氏体以及常规铁素体Π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Π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2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2淬火次数减少;根据Nb2V2Ti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。关键词:超细晶奥氏体; 低碳微合金钢; 循环加热2淬火; 原始组织中图分类号 :TG142133文献标识码 :A文章编号 : 100926264 (2009)0520050205Evolution of ultra2f ine austenite grains in Nb andNb2V2Timicroalloyed low carbon steel under cyclic heating2quenching treatmentYAO Sheng2jie,DU Lin2xiu , L IU Xiang2hua,WANGGuo2dong(State Key Laboratory of Rolling and Automation , Northeastern University , Shenyang 110004 ,China)Abstract : Effects of initial microstructure (warm2rolled ferriteΠpearlite , warm2rolled tempered martensite and ferriteΠbainite) and cycle timesofrepetitiveheating2quenchingtreatmentontheevolutionofultra2fine austenitegrainsinNbandNb2V2Timicroalloyedsteelwereinvestigated.Theresults indicate that much more significant refinement of austenite grains can be expected in Nb2V2Timicroalloyedsteel by cyclic heating2quenching treatment , and the initial microstructure of warm2rolled ferriteΠpearlite is favourable for the refining of austenite grains , and from whichaustenite grains in size of 1～2μm can be obtained for the steel with the repetitive treatment for 3～4 times. Otherwise , less times of repetitivetreatmentisrequiredtoreachtheminimumvalueof austenitegrainsizefortheNb2steel comparedwiththeNb2V2Ti microalloyedsteel. Effectsofthe microalloying on ultra2refinement of austenite grains greatly depend on the amount of dissolved vanadium and niobium , according toTEMobservation and EDS analysis of second2phase particles in Nb2V2Ti steel.Key words :ult