X70钢管道磁化及退磁特性试验研究

管道中的剩磁不仅会影响管道的检测精度,还会使管道内腐蚀速率加快。为了对X70钢管道的磁化及退磁特性进行研究,在X70钢材料特性分析的基础上,采用Maxwell软件建立了X70钢磁化模型,并基于响应面优化设计方法,研究了退磁率与磁感应强度和退磁速度的关系。研究结果表明:X70钢的磁感应强度在永磁铁垂直投影处最强,在垂直投影处以圆波形式向外扩散,磁感应强度逐渐削弱;X70钢中间位置的磁畴相互抵消,剩磁较小,而在永磁铁的正下方磁畴无法相互抵消,所以永磁铁的正下方磁感应强度最大;永磁铁退磁装置的退磁率与永磁铁磁感应强度和退磁装置的退磁速度有关,且永磁铁磁感应强度的影响要远大于退磁装置退磁速度的影响;退磁装置与X70钢之间的相对运动速度为0.6 m/s、永磁铁的磁感应强度为60 mT时,退磁效果最佳,退磁率可达67.60%。所得结论可为X70钢管道的磁化及退磁研究提供依据。

Experimental Study on Magnetization and Demagnetization Characteristics of X70 Steel Pipe

The remanence in the pipe not only affects the detection accuracy,but also accelerates the corrosion rate in the pipe.In order to study the magnetization and demagnetization characteristics of X70 steel pipe,based on the analysis of material properties of X70 steel,the Maxwell software was used to build the magnetization model of X70 steel;and then,based on the optimization design method of response surface,the relationship among demagnetization rate,magnetic induction intensity and demagnetization speed was studied.The study results show that the magnetic induction intensity of X70 steel is the strongest and diffuses outward in the form of circular wave at the vertical projection of permanent magnet,and then gradually weakens;the magnetic domains in the middle of X70 steel offset each other,and the remanence is small,while the magnetic domains below the permanent magnet cannot offset each other,so the magnetic induction intensity below the permanent magnet is the largest;the demagnetization rate of the permanent magnet demagnetizer is related to the magnetic induction intensity of permanent magnet and the demagnetization speed of demagnetizer,and the influence of the magnetic induction intensity of permanent magnet is much greater than that of the demagnetization speed of demagnetizer;when the relative motion speed between demagnetizer and X70 steel is 0.6 m/s and the magnetic induction intensity of permanent magnet is 60 mT,the demagnetization effect is the best,and the demagnetization rate can reach 67.60%.The study results provide a basis for the study of magnetization and demagnetization of X70 steel pipe.