800MPa级冷轧耐候双相钢连续冷却相变及组织性能研究  

Microstructure and mechanical properties of 800 MPa grade cold rolled weathering dual-phase steel and its continuous cooling phase transformation

作　　者：王小鹏[1] 杜林秀[1] 周民 杨星[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,沈阳110819 [2]重庆赛迪冶炼装备系统集成工程技术研究中心有限公司,重庆401122

出　　处：《材料科学与工艺》2013年第1期67-72,共6页Materials Science and Technology

基　　金：国家自然科学基金资助项目(50527402)

摘　　要：为了探索一种800 MPa级冷轧耐候双相钢的连续冷却转变规律及退火后组织性能变化,利用For-master-FⅡ全自动相变仪及连续退火模拟实验机,进行了连续冷却转变(CCT)曲线的测定及连续退火实验.结果表明:实验钢的过冷奥氏体在很低的冷却速度(0.5℃/s)下即可发生马氏体转变,而珠光体转变较少.当冷速为80℃/s时,仅发生马氏体转变;退火后实验钢显微组织中的马氏体呈带状分布,经最优工艺退火后实验钢的显微组织为多边形铁素体(79%)+块状马氏体(16%)+细小的残余奥氏体(5%),残余奥氏体主要分布于马氏体晶粒内部或铁素体的晶界处;实验钢屈服强度为387 MPa,抗拉强度为863 MPa,延伸率为18%,强塑积达到15534.In the present study,to reveal the continuous cooling transformation,microstructure and mechanical properties changes of a new developed weathering dual-phase steel,continuous cooling experiments and annealing experiments were performed by Formaster-FⅡ automatic expansion instrument and continuous annealing simulator.The results show that martensite transformation occur at very low cooling rates（0.5 ℃/s）,and pearlite amount are seldom.The microstructure only consists of martensite when the cooling rate reaches 80 ℃/s;It is shown that the test steels have banded martensite structure after annealing.After optimal annealing process,the microstructure is composed of polygonal ferrite（79%）＋massive martensite（16%）＋fine retained austenite（5%）,the retained austenite grains mainly located inside martenite grains or at ferrite boundaries,and the test steels have excellent mechanical properties：Rp0.2=387 MPa,Rm= 863 MPa,δ=18%,Rm×δ=15 534.

关 键 词：冷轧耐候钢 组织性能 带状组织 残余奥氏体 

分 类 号：TG156.21[金属学及工艺—热处理]