超低碳QT钢焊接二次热循环的组织转变与局部脆化  

MICROSTRUCTURE TRANSFORMATION AND BRIT- TLEMENT OF A ULTRA-LOW CARBON QT STEEL DURING DOUBLE WELDING THERMAL CYCLE

作　　者：高惠临[1] 董玉华[2] R.W.Hendricks 

机构地区：[1]西安石油学院机械工程系,西安710065 [2]西安交通大学材料科学与工程学院,西安710049 [3]VirginiaPolytechnicInstituteandStateUniversity

出　　处：《金属学报》2001年第1期34-38,共5页Acta Metallurgica Sinica

基　　金：中国石油天然气集团公司石油管力学和环境行为重点实验室基金

摘　　要：采用焊接热模拟实验及透射电镜分析技术研究了一种超低碳ＱＴ钢在多道焊接二次热循环过程中的组织转变与韧性间的关系．结果表明，由于在一次焊接热循环过程中的晶粒粗化和未回火马氏体的形成，使得粗晶区的韧性明显降低．在多道焊的二次热循环时，实验钢不存在临界粗晶区局部脆化现象，但表现为亚临界粗晶区局部脆化。引起亚临界粗晶区局部脆化的原因是碳化物的析出粗化和残余奥氏体的热失稳分解．The relationship between microstructure and toughness of the welding heat-affected zone (HAZ) in a ultra-low carbon QT steel (HSLA-100) was investigated using welding thermal simulation experiment and TEM. The experimental results show that the toughness of coarse grained HAZ decreases due to the formation of coarse austenite grain and the appearence of the untempered martensite in the first welding thermal cycle. During the second welding thermal cycle of multi-pass welding, the experimental steel shows no local brittlement in the intercritically reheated coarse-grained HAZ, but a local brittlement appears in subcritically reheated coarse-grained HAZ. This phenomenon is caused by the precipitation of carbide and thermal decomposition of retained austenite.

关 键 词：HSLA-100钢 多道焊 热影响区 脆化 船舶 焊抗热循环 

分 类 号：TG457.11[金属学及工艺—焊接] U668.2[交通运输工程—船舶及航道工程]