摘要
利用外加磁场改善电弧焊焊接工艺,具有成本低、附加耗能少、易操作等优点,已成为当今研究的热点之一。针对高速MIG焊时焊缝成形不良及焊接接头质量差等问题,在焊枪上装配一紧凑型脉冲复合磁场发生器,同时调控电弧和熔滴的左右摆动及前倾行为;并开展不同焊接参数下的铝合金车体长大薄壁型材对接接头焊接工艺试验,以研究高速焊条件下的最佳焊接工艺。研究发现,对于铝合金车体焊缝,励磁参数为8A、120 Hz,焊接参数为265A、23.5 V、1.2 m/min时,焊缝成形质量最佳。利用金相显微镜以及背向散射电子衍射(EBSD)技术表征了不同焊接参数下焊接接头的微观组织,分析了外加脉冲复合磁场对焊接接头组织的影响。结果表明,在高速焊接条件下(>1.0 m/min),焊接接头的晶粒相较于常规焊速时明显粗化,且熔合区宽度有所增加。然而,引入脉冲复合磁场后,晶粒尺寸和熔合区宽度均降低至与常规焊速相当的水平。开展不同焊接参数下的焊接接头力学性能测试,结果表明,外加脉冲复合磁场对焊接接头的机械性能具有显著的改善作用,焊缝区的平均硬度提高了21.37%,而接头的平均抗拉强度达到187 MPa,与传统焊接速度时的193 MPa相当接近。在保证焊缝成形质量和接头机械性能的前提下,最终将焊接速度从0.75 m/min提高到1.2 m/min,实现了优质高效的焊接过程。
The use of external magnetic field to improve the arc welding process has the advantages of low cost,low additional energy consumption and easy operation,which has become one of the hot spots in today's research.In order to solve the problems of poor weld forming and poor quality of welded joints during high-speed MIG welding,this paper carried out the welding process test of butt joints of aluminum alloy car body with large and thin wall profiles under different welding parameters to study the optimal welding process under high-speed welding conditions.It is found that for the weld of the aluminum alloy car body,the welding quality is the best when the excitation parameters are 8 A,120 HZ,and the welding parameters are 265A,23.5V,and 1.2 m/min.Metallurgical microscopy and backscatter electron diffraction(EBSD)were used to characterize the microstructure of welded joints under different welding parameters,and the effects of applied pulsed composite magnetic fields on the microstructure of welded joints were analyzed.The results show that under the condition of high-speed welding,the grain of the welded joint is significantly coarser compared with the conventional welding speed,and the width of the fusion zone is increased.However,with the introduction of pulsed composite magnetic fields,both the grain size and the width of the fusion zone are reduced to a level comparable to that of conventional welding.The results show that the mechanical properties of welded joints under different welding parameters are significantly improved,the average hardness of the weld zone is increased by 21.37%,and the average tensile strength of the joint reaches 187MPa,which is quite close to the 193MPa at the traditional welding speed.Under the condition of ensuring the forming quality of the weld and the mechanical properties of the welded joint,the welding speed was finally increased from 0.75m/min to 1.2m/min,and the high-quality and efficient welding process was realized.
作者
武永寿
韩晓辉
陈姬
李刚卿
李帅贞
左帅
WU Yongshou;HAN Xiaohui;CHEN Ji;LI Gangqing;LI Shuaizhen;ZUO Shuai(CRRC Qingdao Sifang Co.,Ltd.,Qingdao 266111,China;Shandong University,Jinan 250061,China)
出处
《电焊机》
2024年第9期14-23,46,共11页
Electric Welding Machine
基金
山东省重点研发计划(重大科技创新工程)(2021ZLGX01)
国家自然科学基金项目(51775313)。
关键词
铝合金
复合磁场
励磁参数
磁控弧焊
微观组织
力学性能
高效焊接
aluminum alloy
composite magnetic field
excitation parameters
magnetron arc welding
microstructure
mechanical properties
high efficiency welding
