屈服强度700MPa级低合金高强钢焊接接头的组织和性能研究  

Research on microstructure and properties for welded joint of the yield strength700 MPa grade HSLA

作　　者：刘永刚[1] 韦加利 张武[1] 洪永昌[2] 尹孝辉[2] 郑栋材[1] 

机构地区：[1]马鞍山钢铁股份有限公司汽车板推进处,安徽马鞍山243000 [2]安徽工业大学材料科学与工程学院,安徽马鞍山243002

出　　处：《电焊机》2014年第5期94-98,共5页Electric Welding Machine

摘　　要：采用等强匹配设计原则,对屈服强度为700 MPa级的低合金高强钢进行了熔化极气体保护焊接,通过金相显微组织观察和力学性能测定对焊接接头的组织和性能进行了试验研究。试验结果表明,焊接接头的热影响区粗晶区组织为等轴铁素体和粒状贝氏体,焊缝区组织以针状铁素体为主,以及少量先共析铁素体与贝氏体;焊缝区的显微硬度与母材相当。在-40℃时AKV=38 J,焊接接头与母材的抗拉强度比为97.1%,断裂位置在热影响区粗晶区,裂纹源区断口形貌为韧窝和解理台阶的混合型断口。经等强匹配焊接的焊接接头表现为强韧性较高,综合力学性能良好。According to the design principles of equal strong matching, the high strength low ＇alloy steel sheet which the yield strength is 700MPa grade were welded hy Gas metal arc welding. The microstructure and mechanical properties of welded joints were studied by observation of microstructure and mechanical properties measured. The test results show that the microstructure of the coarse grain zone in the heat affected zone was equiaxed ferrite and granular bainite. The microstructure of welded zone was based on acicular ferrite, a little of proeutectoid ferrite and bainite. The hardness of welded zone was equaled to base metal. The Impact energy was 38 J at - 40 ℃. The tensile strength of welded joint can reach the 97.1% of the base metal,the crack position was located the coarse grain zone of heat affected zone. The fracture morphology, of the crack source zone were dimple and Cleavage step. The welded joints had high strength and toughness by equal strong matching welding, it has excellent comprehensive mechanical properties.

关 键 词：低合金高强钢 焊接接头 等强匹配 组织 性能 

分 类 号：TG457.11[金属学及工艺—焊接]