低碳钢焊缝力学性能评价的磁记忆检测试验研究

Experimental Study on Mechanical Properties Evaluation of Weld of Low Carbon Steel by Magnetic Memory Testing

为快速准确检测钢材焊缝质量的力学性能,研究了磁记忆检测技术在低碳钢焊缝质量检测的应用。采用不同的焊接电流对Q235B钢进行对接焊接,采用射线检测技术进行了焊缝质量检测。对不同焊接电流下的试件进行拉伸试验,对不同应力卸载后的焊件进行了磁记忆信号测量,研究了焊件磁记忆信号变化规律与其力学性能的关系。结果表明,不同焊接电流下焊件具有不同的力学性能和磁记忆信号特征。焊件的屈服强度和抗拉强度最大时,不同应力作用下磁性特征参量ΔBmax的平均值即磁特征值D最大,平均磁场梯度Kavg最小。采用磁特征值D和平均磁场梯度Kavg,可以有效判定低碳钢焊缝的力学性能。

In order to test the mechanical properties of steel weld quality quickly and accurately, the application of magnetic memory test technology in weld quality inspection of low carbon steel was studied. The butt welding tests of Q235B steel were carried out by using different welding currents, and the weld quality was tested by radiographic testing. Tensile tests of the specimens under different welding currents were carried out, magnetic memory signal of the specimen after unloading from differe＇nt stresses was measured, and the relationship between the magnetic memory signal change of the specimen and its mechanical properties was studied. The results show that under different welding currents the specimens have different mechanical properties and different magnetic memory signal characteristics. When the yield strength and tensile strength of the specimen are the maximum, the magnetic eigenvalue D which is the average value of magnetic characteristic parameters ΔBmax under different stresses is the maximum, the average magnetic field gradient Kavg is the minimum. The magnetic eigenvalue D and the average magnetic field gradient Kavg can be used to effectively judge the mechanical properties of low carbon steel weld.