采用机器人中频直流伺服焊枪点焊系统对1.2mm厚的AISI 430不锈钢薄板进行了点焊试验，研究了焊接电流对点焊接头力学性能、熔核直径、微观形貌、显微硬度以及拉剪断裂模式的影响规律.结果表明：随着焊接电流的增大，430不锈钢点焊接头抗剪强度增大，当电流达到10kA时，点焊出现飞溅现象，导致接头强度降低.接头熔核区由粗大的铁素体组成，带有少量的马氏体组织和碳化物沉淀.熔核区硬度高于母材区和热影响区，当熔核直径大于 4.8mm时，接头主要发生纽扣断裂；当熔核直径小于 4.8mm时，接头主要发生界面断裂，且一般为脆性断裂.
The experiments of resistance spot welding for AISI 430 Ferritic stainless steel sheet with 1.2mm thickness was carried out by using the robot DC servo spot welding system. The effect of the welding current on the mechanical properties, the nugget diameter, the microstructure, the micro-hardness and the failure mode were researched. The results show that with the increase of welding current, the strength of the joint increases. When the current reaches 10kA, the splashing phenomenon occurs in spot welding, and it leads to the decrease of joint strength. The joint nugget region consists of coarse ferrite with a small amount of martensite and carbide precipitates. The hardness of the nugget area is higher than that of the base metal zone and heat affected zone. Joints mainly occur button fracture when the nugget diameter is more than 4.8mm. When the nugget diameter is less than 4.8mm, it is interfacial fracture, and usually is brittle fracture.
［1］贾凤翔, 侯若明, 贾晓滨.不锈钢性能及选用［M］. 北京: 化学工业出版社, 2013.
JIA Fengxiang, HOU Ruoming, JIA Xiaobin. Stainless steel performance and selection ［M］. Beijing: Chemical Industry Press, 2013.
［2］杨柳, 程轩挺, 孙游, 等. 超高强热成形钢B1500HS的电阻点焊工艺和接头性能［J］.上海交通大学学报, 2012, 46(7): 1103-1106.
YANG Liu, CHENG Xuanting, SUN You, et al. Technology and weldability of resistance spot welding of B1500HS hot-stamped steel［J］. Journal of Shanghai Jiao Tong University, 2012, 46(7): 1103-1106.
［3］沈琦, 李永兵, 李锐华, 等.永磁体作用下电阻点焊熔核中的电磁场分布规律［J］.上海交通大学学报, 2011, 45(1): 25-29.
SHEN Qi, LI Yongbing, LI Ruihua, et al. Magnetic field distribution in resistance spot welding nugget under permanent magnet ［J］. Journal of Shanghai Jiao Tong University, 2011, 45(1): 25-29.
［4］LIU W, SUN C J, XU X, et al. The influences of nugget diameter on the mechanical properties and the failure mode of resistance spot-welded metastable austenitic stainless steel ［J］. Materials & Design, 2012, 33: 292-299.
［5］ALIZADEH-SH M, MARASHI S P H, POURANVARI M. Resistance spot welding of AISI 430 ferritic stainless steel: Phase transformations and mechanical properties ［J］. Materials & Design, 2014, 56: 258-263.
［6］KIANERSI D, MOSTAFAEI A, AMADEH A A. Resistance spot welding joints of AISI 316L austenitic stainless steel sheets: Phase transformations, mechanical properties and microstructure characterizations［J］. Materials & Design, 2014, 61: 251-263.
［7］ZYREK D. An effect of weld current and weld atmosphere on the resistance spot weldability of 304L austenitic stainless steel ［J］. Materials & Design, 2008, 29(3): 597-603.
［8］MA J C, YANG Y S, TONG W H, et al. Microstructural evolution in AISI 304 stainless steel during directional solidification and subsequent solid-state transformation ［J］. Materials Science and Engineering: A, 2007, 444(1/2): 64-68.
［9］李鹏雁, 张勇, 郭连志, 等. 00Cr18Ni10N不锈钢点焊接头显微组织及凝固模式的分析［J］.热加工工艺, 2011, 40(5): 48-51.
LI Pengyan, ZHANG Yong, GUO Lianzhi, et al. Microstucture and solidification mode of joint of 00Cr18Ni10N austenitic stainless steel by spot welding ［J］. Hot Working Technology, 2011, 40(5): 48-51.
［10］BINA M H, JAMALI M, SHAMANIAN M, et al. Investigation on the resistance spot-welded austenitic/ferritic stainless steel ［J］. The International Journal of Advanced Manufacturing Technology, 2014, 75(9/10/11/12): 1371-1379.
［11］POURANVARI M, MARASHI S P H. Similar and dissimilar RSW of low carbon and austenitic stainless steels: Effect of weld microstructure and hardness profile on failure mode ［J］. Materials Science and Technology, 2009, 25(12): 1411-1416.
