Author(s): LIU Yongxiang, JIN Jiabing, ZHANG Wei, Machinery Department, Naval NCO School of Bengbu
Pages: 230-231+234
Year: 2015 Issue:  13
Journal: Hot Working Technology
Keyword:  flux copper backing; different flux; DH40 steel; mechanical property;
Abstract: The research on using FCB submerged arc welded DH40 steel was conducted in the case of different flux,including domestic flux TGF-55 E, Nippon steel flux NSH-55 EM and Kobelcc Flux PF-55 E. The mechanical property and microstructure morphology of joints were discussed. The results show that the elongation and impact toughness are up to the maximum, the elongation is 25.8%, and the average value of impact toughness is 153 J at 0 ℃ as well as 132 J at-20 ℃;meanwhile, the welded seam mainly is composed of acicular ferrite, when Kobelcc Flux PF-55 E is chosen in the welding process. However, the mechanical property of the welded joint welded by Nippon steel flux NSH-55 EM is inferior to the welded joints welded by Kobelcc Flux PF-55 E. The weld metal consists of proeutectoid ferrite, acicular ferrite and few side plate ferrite. The property of the welded joint formed by domestic flux TGF-55 E is worst. The microstructure is composed of proeutectoid ferrite, side plate ferrite and few acicular ferrites.