交流磁场对铜/钢异种材料电弧焊接头组织性能的影响  

Effect of AC magnetic field on microstructure and properties of Cu/steel dissimilar arc welded joint

作　　者：刘艳华 钱娜 王龙 陈国财 程东海[2] LIU Yan-hua;QIAN Na;WANG Long;CHEN Guo-cai;CHENG Dong-hai(School of Intelligent Manufacturing and Energy Engineering,Jiangxi College of Engineering,Xinyu 401520,China;School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063,China)

机构地区：[1]江西工程学院智能制造与能源工程学院,江西新余401520 [2]南昌航空大学航空制造工程学院,江西南昌330063

出　　处：《材料热处理学报》2021年第7期179-185,共7页Transactions of Materials and Heat Treatment

基　　金：江西省教育厅科学技术研究项目(GJJ151300)。

摘　　要：以HS201纯铜焊丝为填充金属,对尺寸均为120L×60^(W)×2^(H)mm的T2紫铜板和Q235钢板进行磁场辅助TIG焊接试验,并对焊接接头的宏观形貌、组织结构、抗拉强度、显微硬度及断口形貌进行分析。结果表明:当焊接电流为95A,焊接速度为95mm/min,磁场电流为0.4-0.6A,励磁频率为25-35Hz时,交流磁场辅助铜钢TIG焊接接头表面成形和力学性能均表现较好,接头的抗拉强度随着磁场电流和励磁频率的增加均呈现先上升后下降的趋势,抗拉强度最高可达223.5MPa,比无磁场提高了44.5%,熔合区硬度最高可达659HV0.2,比无磁场时提高了10.2%。TIG焊接接头各区域硬度值排序为:熔合区>钢侧热影响区>焊缝区>钢母材>铜母材>铜侧热影响区。添加交流磁场前后,TIG焊接接头断裂区由铜侧热影响区转移至焊缝区,断裂方式均为典型的韧性断裂。添加磁场后,熔合区和焊缝区组织均由(α-Fe)+(ε-Cu)的混合固溶体组成,且焊缝区组织细化,其均匀性明显提高,这主要是交流磁场对熔池的电磁搅拌作用,其搅拌过程为:Fe元素扩散到熔池、熔池顺时针搅拌、熔池逆时针搅拌和熔池凝固。The magnetic field assisted TIG welding tests were carried out on T2 copper plate and Q235 steel plate with the size of 120 mm×60mm×2mm using HS201 pure copper wire as filler metal. The macro morphology, microstructure, tensile strength, microhardness and fracture morphology of the welded joint were analyzed. The results show that when the welding current is 95 A, the welding speed is 95 mm/min, the magnetic field current is 0.4-0.6 A, and the excitation frequency is 25-35 Hz, the surface forming and mechanical properties of the TIG welding joint with AC magnetic field are better. The tensile strength of the joint increases first and then decreases with the increase of the magnetic field current and excitation frequency, and the maximum value of tensile strength is 223.5 MPa, which is 44.5% higher than that of without magnetic field, the maximum value of hardness of fusion zone can reach 659 HV0.2, which is 10.2% higher than that of without magnetic field. The order of hardness value of the TIG welding joint is as follows: fusion zone >steel side heat affected zone >weld zone >steel base metal >copper base metal >copper side heat affected zone. Before and after adding AC magnetic field, the fracture zone of the TIG welding joint is transferred from the copper side heat affected zone to the weld zone, and the fracture mode is typical ductile fracture. After adding magnetic field, the fusion zone and weld zone are composed of(α-Fe) +(ε-Cu) mixed solid solution, and the microstructure of weld zone is refined, and its uniformity is obviously improved. This is mainly due to the electromagnetic stirring effect of AC magnetic field on the molten pool. The stirring process is: Fe element diffuses to the molten pool, the molten pool is stirred clockwise, the molten pool is stirred anticlockwise and the molten pool solidifies.

关 键 词：交流磁场 磁场电流 励磁频率 组织细化 韧性断裂 

分 类 号：TG444[金属学及工艺—焊接]