铁素体不锈钢激光填丝焊与MAG焊接头组织与性能研究  

Study on the Microstructure and Properties of Laser Wire Filling Weld‐ing and MAG Welding Joints of Ferritic Stainless Steel

作　　者：房博 许鸿吉[1] 王玮彤 FANG Bo;XU Hongji;WANG Weitong(School of Materials Science and Engineering,Dalian Jiaotong University,Dalian 116028,China)

机构地区：[1]大连交通大学材料科学与工程学院,辽宁大连116028

出　　处：《电焊机》2025年第2期102-107,共6页Electric Welding Machine

摘　　要：针对T4003铁素体不锈钢的焊接性问题,通过对比激光填丝焊与MAG焊的工艺特性,系统分析了两种焊接接头的显微组织演变及力学性能差异。采用对接工艺制备焊接试样,通过金相显微镜、维氏硬度仪、拉伸试验机及扫描电子显微镜(SEM)对接头的显微组织、硬度分布、拉伸性能及断口形貌进行表征。结果表明:激光填丝焊焊缝区显微组织为奥氏体与铁素体双相结构,平均硬度达338 HV,显著高于MAG焊(251 HV),其抗拉强度(548 MPa)较MAG焊接头(469 MPa)提升16.4%;MAG焊接头熔合线区域硬度最高(299 HV),热影响区硬度波动显著,且断后伸长率(12.0%)优于激光填丝焊(8.95%)。两种接头的断裂位置均位于热影响区,弯曲试验中均未开裂,表现出优异的抗弯性能。断口分析表明,两种焊接方法均呈现典型的微孔聚集型韧性断裂特征,但MAG焊韧窝尺寸更大,塑性变形能力更强。本研究为低镍铁素体不锈钢的焊接工艺选择提供了理论依据与数据支持。This study systematically investigates the microstructure evolution and mechanical properties of T4003 ferritic stainless steel joints fabricated by laser wire filling welding and metal active gas welding(MAG).Welding experiments were conducted using butt joint configurations,and the microstructure,hardness distribution,tensile properties,and fracture morphology were characterized via optical microscopy,Vickers microhardness testing,tensile testing,and scanning electron microscopy(SEM).Results indicate that the LWFW joint exhibits a dual-phase microstructure(austenite+ferrite)in the weld zone,with an average hardness of 338 HV,significantly higher than that of MAG joints(251 HV).The tensile strength of LWFW joints(548 MPa)exceeds that of MAG joints(469 MPa)by 16.4%.The MAG joint shows the highest hardness(299 HV)near the fusion line,with pronounced hardness fluctuations in the heat-affected zone(HAZ),and demonstrates superior elongation(12.0%)compared to laser wire filling welding(8.95%).Both joints fractured in the HAZ during tensile testing and exhibited excellent bending resistance without cracking.Fractographic analysis reveals ductile fracture characteristics with dimple aggregation for both methods,while MAG joints display larger and deeper dimples,indicating enhanced plastic deformation capability.This study provides critical insights into the selection of welding processes for low-nickel ferritic stainless steel in industrial applications.

关 键 词：铁素体不锈钢 激光填丝焊接 微观组织 力学性能 

分 类 号：TG456.7[金属学及工艺—焊接]