Analysis of mechanical properties and microstructure of flux-cored wire for railway transportation equipment steel

Aiming at 450 MPa level low-alloy high-strength steel for railway transportation equipment, a flux-cored wire with excellent welding performance, high strength toughness and good fatigue resistance was developed. The tensile property, low-temperature impact toughness, fatigue strength and microstructure of flux-cored wire deposited metal were analyzed. The results indicate that the composition of flux-cored wire is designed reasonaby. The microstructures are mainly acicular ferrite and granular bainite.The grain size is fine. Therefore the strength toughness is effectively improved and the excellent low-temperature toughness and fatigue strength are obtained. The tensile strength, low-temperature impact toughness at-40 ℃ and fatigue strength of flux-cored wire deposited metal achieve 620 MPa,96 J and 354 MPa, which are 1.1,1.6 and 2.2 times of the target value of design respectively. The developed flux-cored wire can meet the welding requirement of 450 MPa level low-alloy high-strength steel for railway transportation equipment.