• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2017, Vol. 53 ›› Issue (22): 30-36.doi: 10.3901/JME.2017.22.030

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Research and Development of Welding Cold Cracking Test Device about High Strength Steel and Experimental Research

JING Hongyang1,2, GUO Huijuan1,2, XU Lianyong1,2, HAN Yongdian1,2, LU Xinyu3, XU Kewang3   

  1. 1. School of Materials Science and Engineering, Tianjin University, Tianjin 300350;
    2. Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, Tianjin 300350;
    3. Offshore Oil Engineering Co., Ltd., Tianjin 300451
  • Received:2017-01-22 Revised:2017-06-06 Online:2017-11-20 Published:2017-11-20

Abstract: Domestic first large-tonnage rigid restraint welding cold cracking tendency test device is self-developed according to the rigid restraint crack test mechanism, which has a precise measuring system and could fully meet the constraint stress holding time of 48h, and the maximum test force of this device is 1200 kN. The rigid restraint crack test of E36 steel plate with butt joint is carried out by using this cold cracking test device and the cold cracking susceptibility of GFL-71NI welding wire (domestic) and DW-A55L welding wire (inlet) are compared and analyzed. Results shows that the critical restraint distance of joint obtained by using GFL-71NI wire is larger than that of DW-A55L wire joint when flux-cored wire gas protection welding method is used, and the critical restraint degree and critical restraint stress of GFL-71NI wire joint are less than that of DW-A55L wire joint by calculating, the cold cracking sensitivity coefficient of GFL-71NI wire joint is higher than that of DW-A55L wire joint and the values are 0.345 147 and 0.326 094 respectively, which indicates that the anti-cracking performance of DW-A55L wire joint is better than that of GFL-71NI wire joint. Metallographic analysis shows that the weld microstructure of DW-A55L wire joint is more uniform and the content of grain boundary ferrite reduces significantly compared with GFL-71NI wire joint; and the content of hardening microstructure in overheated zone of DW-A55L wire joint is less too which significantly reduces the cold cracking tendency of DW-A55L wire joint.

Key words: cold cracking susceptibility coefficient, E36 steel, rigid restraint test

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