Property of WDB620 steel weld joint

From mechanical property and welding defect aspects, the weld properties about crack free low carbon bainite WDB620 steel are investigated using shielded metal arc welding, submerged arc welding and mixed active-gas arc welding method. Based on weldability test, it is indicated that weld joints of WDB620 steel have better tensile strength, bending property and impact toughness at lower temperature. Welding defects of WDB620 steel weld joints on X-rays negative film using three weld methods are analyzed. With Pareto diagrams of defects type being drawn and analyzed, it is found that the main defects types are air hole and slag inclusion, and the crack is very seldom, which indicates WDB620 steel has less crack tendency. According to the result of rank test on welding defect size and mechanical property test, it can be concluded that in the condition of meeting mechanical properties, mixed active-gas arc welding method is recommended for WDB620 steel.