Analysis Of Welding Extrusion Process Of High Frequency Resistance Welded Pipe

In order to deal with the impact of harsh environment in deep sea on oil well pipe,it is urgent to study and develop high strength and high quality thick wall pipe.Extrusion is the key to the production of high-frequency welded pipe welding process,in this paper,resistance to high frequency straight seam welded pipe for the study of the carrier,during the process of heating and extruding section welding simulation method,fully consider the electric field,magnetic field,field,temperature field and stress field of multi field coupling process,pipe extrusion process and the change of residual stress on numerical simulation,research work mainly includes:(1)The method of heating and extrusion section simulation for welding process is proposed.Using software ANSYS to simulate the heating process of high frequency resistance welding,the temperature field of welding point is obtained.The extrusion model was established by using the obtained welding temperature field in the finite element software DEFORM,and the simulation study of the extrusion process was realized.(2)The concept of characteristic value of burr morphology was defined for the process of burr forming.According to the simulation results,the eigenvalue K increases monotonously with the extrusion process until it reaches a stable value,and the eigenvalue K can directly reflect the extrusion degree in the welding process.According to the welding temperature condition,the characteristic value criterion is 0.43?0.49.The maximum equivalent residual stress at the root of the outer burr within the range of the characteristic value is distributed within the range of 360Mpa-420 Mpa,which is far less than the yield strength of the tube billet material.The correctness of the criterion of the characteristic value is verified from the side.(3)The X-ray diffraction method was used to measure the residual stress value of the workpiece produced in the factory,and the comparison showed that the numerical simulation results of the residual stress were consistent with the actual measured values,which verified the accuracy of the three-dimensional numerical simulation results of the straight-seam high-frequency resistance welded pipe in this paper.Using machine vision technology,the criterion of the characteristic value of the burr shape obtained is used to judge the welding quality online in the production process.Compared with the current manual quality control process,the stability and reliability of welding quality will be greatly improved while the welding quality is improved by this method.