将旋转磁场探伤仪的底部关节活动距离转换为磁轭夹角变化,设计了一种磁轭夹角可变的旋转磁场探伤仪并进行验证试验。首先通过理论计算获得旋转磁场的磁场分布及其变化规律,并通过仿真确定磁场变化轨迹以及磁场强度变化程度,以确认理论计算是否正确。然后制作灵敏度试块,测试仪器提升力、有效磁化范围以及缺陷检出灵敏度,确定调节电流相位方法的有效性。试验结果表明,该方法对长度不小于9 mm的自然缺陷可以做到100% 检出。

A rotating magnetic field detector with variable angle of the magnetic yoke was designed by converting the movement distance of the bottom joint of the rotating magnetic field detector into a change in the angle of the magnetic yoke, and the validation tests were conducted. Firstly, the magnetic field distribution and its variation pattern of the rotating magnetic field were obtained through theoretical calculation, and the trajectory and degree of magnetic field intensity variation were determined through simulation to confirm whether the theoretical calculation was correct. Then a sensitivity test block was manufactured to test the instrument's lifting force, effective magnetization range, and defect detection sensitivity, and determine the effectiveness of the current phase adjustment method. The experimental results showed that this method can achieve 100% detection of natural defects with a length of no less than 9 mm.