Thermal Effects Analysis of GTAW and FCAW Welds on the SS400 Steel

Authors

  • Kyung-Hyen Lee
  • Sueng-Dai Kim
  • Bo-An Kang

Abstract

The thermal effects on the gas tungsten arc and flux cored arc welded specimens using SS400 mild steel was analyzed. Heat transfer and residual stress results were used to compare the advantages and disadvantages of each welding method in terms of efficiency. When joining SS400 mild steel plate by V-butt welding, the heat affected zones and heat distribution characteristics of the two specimens welded with GTAW and FCAW were compared according to the welding method and number of passing layers. In the GTAW, main welding was followed after temporary welding using a TIG welder. FCAW used a CO2 welder under rating current 350A. In order to observe the change due to heat, heat transfer and residual stress analysis of each specimen were performed. In the GTAW specimens, the width of the heat affected zone was narrow and there was no change in the weld bead structure. Coarse dendrite tissue was observed in FCAW specimens. This is thought to be due to the difference in cooling rate that occurs between the weld base material and the molten structure. The difference in residual stress of the specimens applied by the two welding methods was not significant. The residual stress was higher in the FCAW method than in the GTAW method. In the case of the FCAW method, the residual stresses were high even in one pass welding, and this result seems to be due to the high current welding. In general, high tensile stress is concentrated around the weld bead, but as the distance from the bead increases, the tensile stress decreases. In the future, the thermal elasto-plastic analysis is conducted by dividing the model applying the thermal energy input FCAW work method in arc welding into the 3-pass model using the GTAW method.

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Published

2020-03-26

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Articles