纵向磁场对低碳钢MIG焊焊缝组织及性能的影响

现代焊接结构对焊接质量的要求越来越高.焊缝金属的内部组织及其结构显著影响焊接接头的性能.为了通过控制焊接接头内部的晶粒形态和尺寸来提高焊接接头的性能，利用纵向磁场发生装置进行了低碳钢MIG焊接实验，对焊缝金属进行了金相及力学性能试验.结果表明，外加纵向磁场作用下与不加磁场进行比较，焊缝的抗拉强度提高了37.79%，焊缝的抗冲击韧性比不加磁场时增加了72.21%.可见外加纵向磁场焊接可以有效地细化焊缝的晶粒，提高焊接接头抗拉强度以及冲击韧性等力学性能.

Effect of longitudinal magnetic field on microstructure and properties of MIG weld joint of mild steel

The request for welding quality in modern welded structures is increasingly high.The microstructure of welding metal has a remarkable influence on the properties of welding joint.In order to control both morphology and size of the grains in the welding joint and to enhance the welding quality,the longitudinal magnetic field was used for the MIG welding of mild steel.In addition,the microstructural observations and the mechanical property tests were performed for the welding joint.The experimental results reveal that for the welding joint with the longitudinal magnetic field,the ultimate tensile strength increases by 37.79% and the impact ductility increases by 72.21%,compared with the welding joint without the magnetic field.The application of the longitudinal magnetic field during welding can effectively refine the grains,and improve the ultimate tensile strength and impact ductility of the welding joint.