High Frequency Induction Heating Of Straight Seam Pipe Welding Residual Stress Analysis

In our country,with the development of oil industry,there are more and more demands of ERW(Electric Resistance Welding).In the course of producing ERW,it is inevitable to bring forth residual stresses, the residual stress distribution is the main reason to the appearance of welding cracks and the reduction of welding joint's strength.It has a great effect on the structural performance such as static strength,fatigue strength,stability,stress corrosion cracking etc.In order to get high quality welding structure,we have to control weld stress.If welding process Can be simulated with computer,we will easily determine the best design,procedure method and optimum welding parameters.Based on summing up other's experience,this paper researcher systemically discusses the theories of temperature field and stress field of welding process and sums up the process of numerical simulation of welding based on finite element analysis software ANSYS. In this project,FEA(Finite element analysis) of plate welding is based upon ANSYS.which is a set of world famous large scaled computational FEA Sofiware.Based on results of high frequency welding heat source,3D solid elements were used in consideration with temperature dependent material properties and effects of phase transition. Using APDL language of ANSYS software, the stress field were obtained by indirect. The high frequency electric resistance welded pipe of temperature and residual stress field were obtained, and the results were analyzed and discussed.The main contents of the paper are as following:the appropriate finite element model is founded; High frequency induction welding current mathematical model can not describe the problem in handling the heat load, the first parameter according to the actual production plants, with the finite element software to simulate the V-angle of the high frequency induction welding temperature field, selected for the welding molding requirements ( Plate edge temperature≥1400℃) Department of the cross section of the temperature field, and record the temperature of each node, use it as a high frequency induction welding heat source.In order to achieve the high frequency welding heat source in the numerical simulation,the ANSYS Parameter Design Language is used.Based On accurate temperature field results, welding residual stress are also calculated by changing thermal elements into structural elements;The tendency of welding residual stress's distribution is presented by post-solution; Analysis of high frequency induction welding residual stress causes the main form, that the temperature gradient was mainly due to the formation of residual stress, axial residual stress close to the material yield stress, the circumferential residual stress is only about one third of the yield stress, radial residual stress values on the smaller projects can be ignored.