不锈钢超薄板光纤激光焊接工艺和性能研究

Study on SUS304 Ultra-thin Sheet withContinuous Fiber Laser Welding

采用波长为1 080nm的光纤激光,对厚度为0.3mm的304不锈钢超薄板进行连续激光搭接焊。在6m/min,0离焦下,600 W可以焊透;超薄板焊接速度可以达到10m/min以上而不会产生驼峰等缺陷。同时,进行了焊缝显微组织的研究。当热输入量较小时,冷却速度较大,焊缝为全奥氏体;当热输入量变大后,焊缝中会夹杂有少量的铁素体。焊缝组织表现为一种"斑块"块状组织,柱状晶不明显,柱状晶由不规则的"斑块"状组织代替,"斑块"由焊缝边缘向中间生长并在焊缝中心交汇,焊缝中心并无等轴晶的形成。区域硬度由高到低依次为母材、热影响区、焊缝,且热影响区为应力薄弱区。扫描电镜显示拉伸断口形貌为韧性断裂,接头抗拉强度为620 MPa。

Processed Continuous-Fiber-laser lap welding to 0.3 mm thickness of SUS304 using fiber laser with 1080 nm.The result shows that the lapped sheets can be welded well using 600 W power with speed of 6m/min.ltra-thin sheet welding speed can reach more than 10m/min without hump and othen defects.Further study have carried out about microstructure.When the heat input is low,thus cooling rate is high,it turn out to be full Austenite.When the heat input behigher,weld seam will have a bit of-Ferrite,and the microstructure shows plaque morphology without obvious columnar grains,in other words,columnar grains are replaced by these plaque structure.It grows from weld seam edge to center and converges in the center.There are not equiaxial grains in the center of weld seam.The hardness of weld seam is lower than HAZ,in which the hardness is lower than base metal.When proceeding mechanical tensile,fracture shows a ductile fracture,and tensile strength is 620 MPa.