Journal of South China University of Technology(Natural Science Edition) ›› 2018, Vol. 46 ›› Issue (10): 81-87.doi: 10.3969/j.issn.1000-565X.2018.10.011

• Mechanical Engineering • Previous Articles     Next Articles

Microstructure and Property of Capacitor-Discharging Projection Welding Joints of T-Type Galvanized Nuts to Hot-Stamping Steels

 ZHOU Zhaoyao1 LUO Jiehan1 ZOU Chunhua2 ZOU Chunya2    

  1.  1． School of Mechanical and Automotive Engineering，South China University of Technology，Guangzhou 510640，Guangdong，China;
    2． Heron Intelligent Equipment Co. ，Ltd，Guangzhou 510900，Guangdong，China
  • Received:2018-01-22 Revised:2018-06-08 Online:2018-10-25 Published:2018-09-01
  • Contact: 周照耀(1965-)， 男，教授，博士生导师，主要从事金属材料成形工艺、组织及性能研究 E-mail:zhyzhou@scut.edu.cn
  • About author:周照耀(1965-)， 男，教授，博士生导师，主要从事金属材料成形工艺、组织及性能研究
  • Supported by:
    Science and Technology Planning Project of Guangdong Province， China( 2016A010103006) 

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Abstract: Resistance projection welding of speed nuts to USIBOR1500 hot-stamped steels was analyzed by the capacitor discharging welding process (CDW). In this investigation, mechanical properties, weld physical attributes and metallographical examinations were used to evaluate the suitable CDW conditions. Hardness characteristics, failure mode and fracture morphology were studied. With the increase of welding volts, nugget size and pull-out strength increase before expulsion, and failure mode changes to PF- and PF-IF mode from IF mode. Quasi cleavage fracture surface was observed on fracture of IF mode. Slip separation and quasi cleavage fracture surface were found on fracture of PF and PF-IF mode. Pronounced HAZ softening was observed on ICHAZ and SCHAZ zone due to the appearance of bainite, ferrite and tempered martensite.

Key words: capacitor discharge welding, Ttype galvanized nut, hotstamping steel, mechanical properties, microstructure, fracture morphology

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