罗震^1,2, 梁建超^1,2, 李洋^1,2, 郭璟^1,2, 张禹^1,2, 宋仁峰³
AuthorsHTML:罗震^1,2, 梁建超^1,2, 李洋^1,2, 郭璟^1,2, 张禹^1,2, 宋仁峰³
AuthorsListE:Luo Zhen^1,2, Liang Jianchao^1,2, Li Yang^1,2, Guo Jing^1,2, Zhang Yu^1,2, Song Renfeng³
AuthorsHTMLE:Luo Zhen^1,2, Liang Jianchao^1,2, Li Yang^1,2, Guo Jing^1,2, Zhang Yu^1,2, Song Renfeng³
Unit:1. 天津大学材料科学与工程学院，天津 300350；2. 天津大学天津高新技术重点实验室，天津 300350；3. 鞍山钢铁矿业设计研究院，鞍山 114004
Unit_EngLish:1．School of Materials Science and Engineering, Tianjin University, Tianjin 300350, China
2．Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, Tianjin 300350, China
3．Anshan Iron and Steel Group Mining Design and Research Institute, Anshan 114004, China
Abstract_Chinese:针对AISI420马氏体不锈钢的焊后脆性问题, 研究了回火脉冲对电阻点焊接头力学性能的影响．分别在普通焊接循环100 ms、600 ms后施加2 kA回火脉冲, 研究熔核区微观组织变化和点焊接头抗拉剪载荷能力, 结果表明：当焊接电流较低时, 只有在较长时间间隔(600 ms)后施加回火脉冲, 熔核区显微硬度与接头力学性能才有明显变化; 当焊接电流较高时, 两种回火脉冲工艺均能明显提高接头力学性能．回火脉冲促进熔核区马氏体分解为铁素体与碳化物, 使断口微观断裂特征从准解理断裂转变为韧窝断裂．
Abstract_English:To deal with the brittleness of AISI420 martensitic stainless steel after welding，a pulse current was exerted after resistance spot welding，and then the effect of the current on the joints’ mechanical properties was investigated. In order to study the changes in microstructure and tensile-shear loads of joints，2 kA tempering pulse current was exerted after welding 100 ms and 600 ms. The results show that the microhardness and mechanical properties change obviously only when the pulse was exerted after 600 ms interval at low welding current; but the mechanical properties change obviously when the pulse was exerted after both 100 ms and 600 ms intervals at high welding current. Martensite is decomposed into ferrite and carbides，which is promoted by the tempering pulse current. In this case，the feature of the fractured joints at microlevel changes from quasi-cleavage fracture to dimple fracture.
Keyword_Chinese:电阻点焊; AISI420马氏体不锈钢; 回火脉冲; 马氏体低温回火
Keywords_English:resistance spot welding; AISI420 martensitic stainless steel; tempering pulse; low temperature tempering of martensite

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