Friction stir spot welding of SPCC low carbon steel plates at extremely low welding temperature
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2019年第5期
论文作者：Y.F.Sun H.Fujii Y.Sato Y.Morisada
文章页码：733 - 741
摘 要：Friction stir spot welding（FSSW） was applied to 2.0 mm thick steel plate cold-rolled commercial（SPCC）low carbon steel plates at a very low rotation speed that ranged from 5 to 50 rpm, which was much lower than that generally used for the conventional FSSW technique. Due to the very low heat input, the welding processes could therefore be completed at a peak welding temperature below 160℃. As a result,a significantly refined microstructure with an average grain size of about 0.41 μm was formed in the stir zone of the joints and the J1{0–11}<-211> and J2{1–10}<-1–12> shear textures were the dominant components, which are different from the D1{11–2}<111> and D2{-1–12}<111> shear textures formed in the conventional FSSW joints. In addition, no heat affected zone could be detected along the crosssectional plane of the joints. Although a few void-like non-bonded areas were still observed along the interface between the upper and lower steel plates, the shear tensile loads of the joints increased to about 10.0 kN when welded at a condition of 8 t, 20 rpm and 30s, and the joints fractured through the plug failure mode.
Y.F.Sun1,2，H.Fujii1，Y.Sato1，Y.Morisada1
1. Joining and Welding Research Institute, Osaka University2. School of Materials Science and Engineering, Zhengzhou University
摘 要：Friction stir spot welding（FSSW） was applied to 2.0 mm thick steel plate cold-rolled commercial（SPCC）low carbon steel plates at a very low rotation speed that ranged from 5 to 50 rpm, which was much lower than that generally used for the conventional FSSW technique. Due to the very low heat input, the welding processes could therefore be completed at a peak welding temperature below 160℃. As a result,a significantly refined microstructure with an average grain size of about 0.41 μm was formed in the stir zone of the joints and the J1{0–11}<-211> and J2{1–10}<-1–12> shear textures were the dominant components, which are different from the D1{11–2}<111> and D2{-1–12}<111> shear textures formed in the conventional FSSW joints. In addition, no heat affected zone could be detected along the crosssectional plane of the joints. Although a few void-like non-bonded areas were still observed along the interface between the upper and lower steel plates, the shear tensile loads of the joints increased to about 10.0 kN when welded at a condition of 8 t, 20 rpm and 30s, and the joints fractured through the plug failure mode.
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