直流磁场作用下高强钢焊接接头组织力学性能的演变

Evolution of Microstructure and Mechanical Properties of Welded Joint of High Strength Steel Under DC Magnetic Field

在WQ960高强钢的GMAW焊接过程中施加直流磁场,通过外加磁场的电磁搅拌作用改变传统GMAW焊接过程的传质传热过程,实现对焊接接头力学性能的改善。为了分析外加直流磁场对高强钢焊接接头性能的影响,对不同磁场参数下焊接接头的拉伸性能、冲击性能、硬度和微观组织进行了检测,探究其组织性能的演变规律及机理。结果显示,当磁场电流为2.5 A时,焊接接头的力学性能达到最佳状态,其抗拉强度为750 MPa,冲击功为70 J,显微硬度为468 HV。这是因为电磁搅拌作用可以细化晶粒,减少先共析铁素体的析出,从而使焊接接头的力学性能提高。

The WQ960 high strength steel was welded by GMAW under DC magnetic field. The magnetic field can improve the mechanical properties of the welded joints by electromagnetic stirring action to change the traditional GMAW welding process heat and mass transfer processes. In order to analyze the action of DC magnetic field to strength steel welded joint, the tensile properties, impact resistance, hardness and microstructure were detected under different magnetic field current. The law of high-strength steel welded joint and mechanism of evolution were explored. The results show that the optimal mechanical properties of the welded joint is obtained, when the magnetic field current is 2.5 A. Then, the mechanical properties of the welded joints are： tensile strength of 750 MPa, impact energy is 70 J, hardness of 468 HV. This is because the electromagnetic stirring can refine the grain, reduce eutectoid ferrite precipitation and improve the mechanical properties of the welded joints.