Microstructure and Mechanical Properties of Welded Joint of S355J2G3 Low-Alloy Steel

Mechanical properties and microstructure of S355J2G3 low-alloy steel MAG welded joints were studied through tensile test, bending test, impact test, hardness examination as well as microstructure analysis. The results showed that tensile, bending and impact properties of the welded joint were all good in case which was welded with G38 3 G3Si; and hardness of the welded joints distributed uniformly, while the highest value of hardness was below 380 HV. The microstructure of the weld seam contained block-shaped pro-eutectoid ferrite that located at the columnar grain boundaries, while fine and dense acicular ferrite and pearlite presented in the grains; the heat-affected zone mainly consisted of pro-eutectoid ferrite, acicular ferrite, pearlite, and a little granular bainite; the base metal contained fine ferrite and pearlite.