Study On Characteristic Value And Evaluation Method Of Metal Magnetic Memory Detection

Special equipment has been widely used in oil filed.In the process of equipment use,because of the existence of stress concentration phenomenon,it is easy to cause damage to special equipment,producing security issues.So it is particularly important to detect special equipment used in oil filed early warning.At present,in the process of magnetic memory testing,there is also a lack of a systematic evaluation method in the filed of special equipment.Consequently,we can not determine whether the equipment can work normally timely and effectively in the testing process.According to the above problems,this topic through experiment research and numerical simulation method of combining the carried out related research.The paper obtains the stress value under different loading,through making the 20 g,15CrMo,Q235-B,Q345,35 CrMo,0Cr18Ni9 six material without defects such as tensile specimen and 20 g,15CrMo two materials zero defect elbow,pipe fillet weld finite element simulation for typical components.Using universal testing machine,hand pump,strain gauge and magnetic memory detector to stretch tensile specimens,fillet and bend down test,we get the stress and strain data,magnetic memory testing data.Through comparatively analyzing strain testing data and the finite element simulation data,we find the error is less than 10%,which proves that the finite element simulation is effective.By adopting MATLAB wavelet noise reduction and MM-SYSTEM magnetic memory processing software to analyze and process the collected magnetic memory signal,we establish a link between stress and magnetic field gradient value model by 20 g.Then we can verify the applicability of the related model by analyzing the elbow,fillet weld two typical component of magnetic memory testing signals.Of round hole defects,crack defects,lack of penetration defects of tensile specimens,elbow,finite element simulation for fillet weld as well as the stress and strain testing and magnetic memory testing,analyzing of magnetic memory signal containing defects,we get the different characteristics of different defect magnetic memory testing signals,which perfects the diagonal weld,bend of two kinds of typical structure evaluation method research.According to the common working condition of typical structures,we simulate 60? high temperature for the bend and fillet weld,concluding that the stress value.Combining high temperature stress value with stress simulation-magnetic field gradient associated model to deduce the magnetic field gr adient,it perfected the typical structure evaluation method.