填充材料对液压支架用Q690高强钢焊接接头组织及性能的影响  

Influence of Filler Material on Microstructure and Properties of Q690 High Strength Steel Welded Joint for Hydraulic Support

作　　者：樊巧芳 林浩 张波 FAN Qiaofang;LIN Hao;ZHANG Bo(Jiangsu College of Safety Technology,Xuzhou 221011,China;Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110000,China)

机构地区：[1]江苏安全技术职业学院,江苏徐州221011 [2]中国科学院金属研究所,辽宁沈阳110000

出　　处：《热加工工艺》2021年第23期146-149,共4页Hot Working Technology

基　　金：江苏省高校“青蓝工程”资助项目(014000773/2018-00376)。

摘　　要：分别采用低温相变焊丝和ER70-G焊丝对液压支架用800MPa级高强钢Q690进行了GMAW对接焊,焊后对焊缝金属的显微组织、相变特征、冲击性能以及接头的拉伸性能和残余应力分布进行了研究。结果表明:低温相变焊丝的焊缝组织为板条马氏体和残余奥氏体,板条马氏体束平均尺寸为22μm,ER70-G填充焊缝组织为针状铁素体和少量粒状贝氏体。低温相变焊丝的焊缝金属Ms点为190℃,Mf点小于0℃,由相变引起的线性膨胀率为0.72%;ER70G填充焊缝在465℃开始发生组织转变,在388℃结束,由相变引起的线性膨胀率为0.31%。低温相变焊丝填充接头焊缝区为压应力,ER70-G填充接头焊缝区为拉应力,说明低温相变焊材可有效降低焊接接头的残余拉应力。两种焊丝所得接头均可满足Q690的力学性能要求,且焊缝冲击断口断裂形式均为韧性断裂。The GMAW butt welding tests of 800 MPa grade high strength steel Q690 for hydraulic support were carried out with low-temperature phase transition wire and ER70-G wire, respectively. After welding, the microstructure, phase change characteristics, impact property of the weld metals and the tensile properties and residual stress distribution of the welded joints were studied. The results show that the microstructure of the weld with low-temperature phase transition wire is lath martensite and residual austenite, the average size of lath martensite beam is 22 μm, the ER70-G filled weld is acicular ferrite and a small amount of granular bainite. The Mspoint of the weld with low-temperature phase transition wire is 190℃and the Mfpoint is below 0℃, the linear expansion rate caused by phase transition is 0.72%. The phase transition of ER70 G filler weld begins at 465℃ and ends at 388℃, and the linear expansion rate caused by phase transition is 0.31%. The residual stress of low-temperature phase transition wire filled weld zone is compressive stress, and the residual stress of ER70-G wire filled weld zone is tensile stress, which indicates that the low-temperature phase transition filler material can effectively reduce the tensile residual stress of welding joint. The welding joints obtained with the two fillers can meet the mechanical properties of Q690 steel, and the impact fracture mode of the two welds is ductile fracture.

关 键 词：高强钢 填充材料 低温相变焊丝 残余应力 

分 类 号：TG407[金属学及工艺—焊接] TG444.77