空冷弛豫对X70级抗大变形管线钢组织性能的影响  

Influence of air-cooling relaxation on microstructure and properties of X70 pipeline steel with high deformation resistance

作　　者：焦多田[1] 蔡庆伍[1] 武会宾[1] 冉旭[1] 任毅[2] 

机构地区：[1]北京科技大学高效轧制国家工程研究中心,北京100083 [2]鞍钢技术中心,辽宁鞍山114001

出　　处：《材料热处理学报》2009年第5期101-105,共5页Transactions of Materials and Heat Treatment

基　　金：国家"十一五"科技支撑计划(2006BAE03A06)

摘　　要：用显微组织分析,力学性能检测以及SUPPA55场发射扫描电镜,研究轧后空冷弛豫对X70级抗大变形管线钢综合性能的影响。结果表明,在相同的轧制工艺下,试验钢随着空冷弛豫时间延长,入水温度降低,先共析铁素体的量和析出物的量都逐渐增多,前者的软化效果与后者的析出强化共同作用,使强度和塑性变化复杂化。试验钢存在最佳的一个入水温度区间,获得先共析铁素体+贝氏体的双相组织,两者呈层状交叠分布,在软化和强化效果的综合作用下得到了抗大变形管线钢X70级所要求的强度塑性最佳匹配。The microstructure and mechanical properties of X70 pipeline steel with different air-cooling relaxation time after rolling was studied by using a SUPPA55 field emission scanning electron microscope and tensile testing. It is found that with extension of relaxation time, the water-entry temperature reduces, the quantity of proeutectoid ferrite and precipitation increases, the change of strength and plasticity becomes complex because of the combination of softening effect by the former and precipitation strengthening by the latter. The results show that a dual phase microstructure of proeutectoid ferrite and bainite with altematively layer distribution is obtained in the steel with water-entry temperature of 700℃ after hot-rolling the air-cooling relaxation, by which a good combination of strength and ductility X70 pipeline steel with high deformation resistance is obtained.

关 键 词：X70级管线钢 弛豫时间 双相组织 抗大变形 

分 类 号：TG142.1[一般工业技术—材料科学与工程]