不锈钢车体板材搭接与对接激光焊接接头的拉伸断裂行为研究  

Fracture Behavior and Performance of Overlap and Butt Laser Welding Joints of Austenitic Stainless Steel Car Body Sheets

作　　者：刘亚姣[1] 刘伟[1] 夏海涛[1] 林基安[1] 王洪萧 王春生[2] 

机构地区：[1]北京交通大学机械与电子控制工程学院,北京100044 [2]中国北车长春轨道客车股份有限公司技术中心,吉林长春130062

出　　处：《铁道学报》2014年第1期28-33,共6页Journal of the China Railway Society

基　　金：铁道部科技研究开发计划(2011J015-B)

摘　　要：用1．5mm厚、牌号为301L-DLT、31L-HT的不锈钢冷轧板分别制备搭接部分熔透、无填料对接的激光焊接试件以研究焊缝结构对断裂行为和机械性能的影响。试件激光焊缝的金属柱状晶直径为10～20／Lm，金相组织为了奥氏体和少量6铁素体；焊缝平均硬度为HV215。实验结果显示：试件的热影响区很窄，晶粒尺寸为20～30μm；301LHT板材的搭接接头断裂模式为外板拉伸断裂，对接接头为焊缝断裂，2种接头的断裂变形都较小；301L—DLT板材的搭接接头表现为焊缝拉剪断裂，对接接头为板断裂，2种接头的断裂变形都很大；301LDLT板材焊件的断裂强度略高于301L—HT板材的同类焊件，同一板材的对接接头断裂强度高于搭接接头；301L板材的激光焊缝柱状晶金属的抗弯性能优异，抗拉强度超过800MPa。Both cold rolled 301L DLT and 301L-HT austenitic stainless steel 1.5 mm plates were used to pre-pare partial depth fused overlap plates laser welding and butt laser welding samples. The weld structure and the hardness distribution in welded samples were examined; the impacts of the weld geometry on fracture be-havior and mechanical properties were investigated. The diameter of metal columnar crystals in 301L laser weld was 10-20 μm, which was composed of Y austenite and a little of 3 ferrite, and their average hardness was HV 215. The HAZ region was small and the grain size was 20-30 μm. 301L-HT fracture modes of over-lap and butt welded joints were respectively tensile-fracture in the outside plate and the weld-fracture, and their frac-ture deformations were small. 301L-DLT over-lap and butt joints exhibited weld tensile-shear fracture and plate-fracture, and both of them gave large fracture deformations. Tensile strengths of 301L-DLT weldments were slightly higher than that of 301L-HTs, and the butt weld were higher than the over-lap weld for the same plate welding. The laser weld of 301L exhibited good bending performance and tensile strengths exceeding 800 MPa.

关 键 词：301L冷轧板 搭接激光焊 对接激光焊 断裂行为 力学性能 

分 类 号：U270.4[机械工程—车辆工程] TG456.7[交通运输工程—载运工具运用工程]