X70级抗大变形管线钢的组织与性能  

Microstructure and Mechanical Property of X70 Grade High Deformability Pipeline Steel

作　　者：赵连玉[1] 张志军 史显波[1,3] 严伟[1] 单以银[1] 杨柯[1] 

机构地区：[1]中国科学院金属研究所,辽宁沈阳110016 [2]河北钢铁集团舞阳钢铁有限责任公司,河南平顶山462500 [3]辽宁科技大学材料与冶金学院,辽宁鞍山114051

出　　处：《钢铁》2013年第7期65-69,88,共6页Iron and Steel

基　　金："十二五"国家科技支撑计划资助项目(2011BAE25B03)

摘　　要：通过成分设计、相变规律研究、工业规模试制,分别获得了(PF+B)双相组织及AF组织的管线钢钢板。二者的试验研究结果表明,当弛豫终止温度低于相变开始温度后,组织中将出现多边形铁素体(PF)。弛豫终止后以20℃/s左右的冷速加速冷却时,未转变的奥氏体转变为由粒状铁素体(GF)及贝氏体铁素体(BF)组成的贝氏体B组织。相比于AF组织管线钢,(PF+B)组织管线钢具有较低的屈强比及较高的伸长率。试验获得的(PF+B)组织管线钢的轧板厚度达30.8mm,强度级别达到X70级,拥有较低的屈强比和较高的伸长率,满足海底管线对抗变形性能的要求。The（PF＋B） dual-phase microstructure steel and AF microstructure steel were obtained based on alloy design,phase-transformation study and industrial trail rolling.Studies on microstructure and mechanical property of the（PF＋B） steel and AF steel show that the polygonal ferrite（PF） phase appears when the relaxation is made below the Ar3 point,bainite（B） microstructure which is mainly composed of granular ferrite and bainite ferrite is obtained with accelerated cooling at 20 ℃/s after the termination of relaxation at proper temperature.The mechanical property of（PF＋B） dual-phase microstructure shows obvious differences with the traditional AF microstructure.The steel with（F＋B） microstructure has lower yield/tensile ratio and higher elongation than the AF microstructure steel,indicating a better deformability.An X70 grade pipeline steel with（F＋B） microstructure was obtained,with wall-thickness of 30.8 mm,which can meet the requirement for the offshore pipeline steel.

关 键 词：管线钢 抗大变形 双相组织 力学性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程]