Effect of Microstructure on High-Strength Low-Alloy Steel Welded Joint Toughness with Simulation of Heat-Affected Zone Coarse-Grained Area

A simulated coarse-grained heat affected zone microstructure formation mechanism is established in high strength low alloy steels using electron backscatter diffraction (EBSD). The governing effect of dispersion and ratios between different types of ferritic structural constituents on variation in impact strength is demonstrated. It is assumed from results of simulating a heat affected zone coarse-grained area that a reduction in welding energy input leads to a shift in ductile-brittle transition temperature towards a lower temperature.