工艺参数对304不锈钢薄板激光焊接接头组织及力学性能的影响

Effect of Process Parameters on Microstructure and Mechanical Properties of Laser Welded 304 Stainless Steel Sheet

研究了不同焊接参数对0.8 mm厚304不锈钢薄板激光焊接接头显微组织和力学性能的影响。结果表明:焊缝区组织为树枝状的δ-铁素体析出在奥氏体基体上,焊缝边缘处的组织形貌为垂直于熔合线生长的柱状树枝晶。当焊接功率为1200 W,焊接速度为1200 mm/min,离焦量为+3 mm,送丝速度为1300 mm/min时,获得的焊接接头抗拉强度最高,为656 MPa,断后伸长率为49.8%,且拉伸断口中存在大量韧窝,属于典型的韧性断裂。同时,该工艺下焊接接头的硬度值也较高,热影响区硬度比母材提升了17.67%,焊缝区硬度比母材提升了11.16%。

The effects of process parameters on the microstructure and mechanical properties of the 0.8 mm thick 304 stainless steel sheet laser welding joints were investigated.The results show that the microstructure of weld zone is dendriticδ-ferrite precipitated on the austenite matrix,and columnar dendrites grown perpendicular to the fusion line appear at the edge of weld.When the welding power is 1200 W,the welding speed is 1200 mm/min,the defocusing amount is+3 mm,and the wire feeding speed is 1300 mm/min,the welded joint has the highest strength of 656 MPa,and the elongation is 49.8%.Furthermore,the fracture of the tensile specimen has a large number of dimples,which is a typical ductile fracture.Additionally,the hardness of the welded joint is also higher,the hardness of the heat affected zone is 17.67%higher than that of the base metal,and the hardness of the weld zone is 11.16%higher than that of the base metal.