激光功率对3/4H SUS301和SUS316异种不锈钢激光点焊成形特征及组织性能的影响  

Effect of Laser Power on Laser Spot Welding Forming Characteristics and Microstructure Properties of 3/4H SUS301 and SUS316 Dissimilar Stainless Steel Laser Spot Welding Joints

作　　者：董智龙 彭丽雯 侯军才[1] 张秋美[1] 张会[1] DONG Zhilong;PENG Liwen;HOU Juncai;ZHANG Qiumei;ZHANG Hui(School of Materials Science and Engineering,Shaanxi University of Technology,Hanzhong 723001,Shaanxi,China)

机构地区：[1]陕西理工大学材料科学与工程学院,陕西汉中723001

出　　处：《焊管》2024年第5期33-39,共7页Welded Pipe and Tube

基　　金：陕西省科技厅攻关项目“传感器用FeCrCoW高电阻合金的开发应用”(项目编号2024GX-YBXM-376);陕西理工大学大创项目(项目编号202310720141)。

摘　　要：采用准连续激光器对测力传感器的3/4H SUS301弹性体和SUS316支撑体进行异种不锈钢激光焊接,探讨了激光功率对点焊接头成形特征和力学性能的影响。研究表明,采用准连续激光模式,在脉冲时间为2 ms、激光功率为180 W至270 W范围内,弹性体焊后的角变形量随着激光功率的增大而增大,激光功率为270 W时弹性体焊后的角变形远低于传感器容许的变形量。当激光功率为210W时,在焊接界面处产生气孔缺陷,焊接功率增大至270 W时,在匙孔底部形成严重的气孔缺陷。焊缝内部以胞状晶方式生长,从熔合区两侧向焊缝中心生长为粗大的柱状晶,焊缝中心为等轴状的树枝晶,随着激光功率的增大,等轴晶区域的宽度减小。焊缝区承受较高的焊接热量使得焊缝区内形变组织发生不完全再结晶,致使形变诱发马氏体相变被抑制,α'马氏体含量降低。点焊接头的剪切力随着激光功率先增大后减小,当激光功率为250 W时,接头的剪切力达到最大值0.49 kN,远高于行业要求。Dissimilar metal laser welding was carried out between 3/4H SUS301 and SUS316 stainless steel which were acted as elastomer and support body of force measuring sensors by using quasi⁃continuous wave laser.The effect of laser power on the influence of forming characteristics and mechanical properties of the spot welded joint was investigated.It was shown that angle distortion was increased with an increase of laser power when a quasi⁃continuous laser was adopted of which the laser power was varied from 180~270 W with a regular pulse time of 2 ms.And the angle distortion was much lower than the allowable deformation of the force measuring sensor when the laser power of 270 W was applied.Porosity defects were detected on the interface of the spot weld under a lower laser power of 210 W and it was formed again in the bottom zone of the keyhole of the spot welded joint when a higher laser power of 270 W or above was used.For the grain shape of the sopt welded joint,celluar crystals grew from the both sides of fusion area to the weld center resulting in growing into columnar crystal.And equiaxed dendrites was formed in the center zone of the spot welded joint.The width of exquixed crystal region was decreased with an increase of laser power.Incomplete recrystallization occurred in the deformed structure due to its exposure to a higher temperature in the spot weld resulting in inducing a inhibition of the deformation induced martensitic transformation.Hereby,the composition of α' martensitic was decreased. Shear strength of the spot weld joint was increased and then was decreasedwith an incrase of laser power. The maximum shear strength of the spot weld joint reached to 0.49 kN which was much higherthan the industry standard when a laser power of 250 W was applied.

关 键 词：激光焊接 点焊 晶粒形态 气孔缺陷 显微组织 

分 类 号：TG146.2[一般工业技术—材料科学与工程]