Study on Mechanical Properties and Microstructure of Q460NH Joint Welded with Flux Cored Wire

Q460NH is a low-alloy high-strength weathering steel. It was welded with self-made CHT81W2 flux cored wire.And the welding joint with reasonable structure and good mechanical performance was obtained. The microstructure of the weld zone is mainly proeutectoid ferrite, plate ferrite, acicular ferrite and granular bainite. The microstructure of the heat affected zone is mainly lath bainite and granular bainite.The microhardness of weld, heat affected zone and base metal shows gradient distribution, and the hardness value decreases in turn. The low temperature impact toughness of each zone of the welded joint meets the requirements of the standard and it has good impact property. The fracture mode of base metal is mainly ductile fracture, and the micromorphology of the fracture is mainly dimples.The fracture morphology of the weld and heat affected zone is dimples+quasi cleavage.