Overlapping Features and Microstructures of Coarse Grain Heat-Affected Zones in Swing Arc Narrow Gap GMA Welded EH40 Grade Steels

Swing arc narrow gap GMA welding experiments were carried out with a Box–Behnken response surface design. Weld metal and heat-affected sizes measured from the joints obtained, an ANOVA was performed to obtain well-fitting models for definition of length. Overlapping patterns microstructures analyzed observed in zones within length through thickness direction. In addition, thermal processes typical HAZs calculated by FEM explain coarse grain (CG-HAZs) simulated attached. It realized that single pass could only be confused austenitized process two passes. The zone divided into unaltered (UACG-HAZ), supercritically reheated (SCRCG-HAZ) intercritically (IRCG-HAZ). is likely there would UACG-HAZ upon UACG-HAZ. CG-HAZs mainly lath bainite little acicular ferrite; SCRCG-HAZ short bainite, granular ferrite IRCG-HAZ massive textures secondary austenite decomposition products. cooling times transformation procedures similar one another significantly longer than those cycle, which caused increase compared CG-HAZs. prior differences among