Magnetic Memory Test Study On Different Angles Welds Of A106 Steel Tube And Defects Of Flat Plate Welding

Due to the complicated shape of welded steel pipe fillet welds,it is difficult to carry out surface treatment and detection analysis by conventional non-destructive testing methods.However,as welding defects that are prone to hazards,weld cracks may cause catastrophic accidents and accurately detect them.It is the key to ensuring production safety.As a new type of non-destructive testing technology,metal magnetic memory testing has been widely used in many industries such as aerospace,chemical industry and petroleum.However,metal magnetic memory technology can only be used for qualitative detection in engineering practice,rather than quantitative analysis.In this paper,the combination of finite element simulation and experimental research is used to detect and analyze three types of welding defects,such as welded steel pipe with buried defects,flat welding crack and two-plate welding,to extract the magnetic memory signal changes of defects on different surfaces.And quantitative analysis of its eigenvalues to provide theoretical basis for engineering applications.Taking the A106 alloy steel commonly used in petrochemical enterprises as the research object,the finite element analysis software was used to extract the magnetic memory signals on the surface of the specimen under different load conditions,and the relationship between the load and the signal characteristic value was obtained as a power function.The tensile test is designed to measure the magnetic memory signal on the surface of the test piece.The results are consistent with the simulation law.The quantitative relationship is optimized by experiment to obtain the relationship between the load value and the characteristic value of the magnetic memory signal.Taking Q345 steel as the research object,the variation law between load value,crack defect size and magnetic memory signal characteristic value is quantitatively analyzed.The results show that the load value and the signal characteristic value have a power function relationship,and the crack length and signal The eigenvalues have a linear relationship,and when the crack width is 1 mm,the tangential magnetic field is reversed,and the peak value of the normal magnetic field appears to be the maximum.For the upper and lower plate welding,due to the shielding effect of the upper plate material,the amplitude of the surface magnetic memory signal is weakened,and no defect signal is detected on the surface of the test piece within a certain stress concentration range.