Numerical Simulation And Measurement Of Welding Residual Stress In The 921A Steel Plate

Welding is a complicated physicochemical process which involves in electromag- netism,heat transferring, metal melting and solidifying, phase transition, welding stress and deformation and so on. In order to get high quality welding structure, we have to control these factors. If welding process can be simulated with computer, we will easily determine the best design, procedure method and optimum welding parameter.Based on the ANSYS, the numerical simulation of residual stress fields in the multi-pass welding of 921A mid-thick plates is accomplished in this paper. Computer programs for the hot-structure coupling analysis of welding transient state are designed by using the ANSYS APDL language.The variation of thermal-physical properties and mechanical properties of material with temperature is fully considered in the finite element analysis. The distribution of transversal residual stress in welding material was measured using X-ray method and electrochemical corrosion. The calculating and measuring results show that: in the welded plate, the transversal residual stress at the weld and weld vicinity are tensile, the residual stress peak value, which value decreases gradually with the distance away from axis of weld, is found in welded toe; the calculated results are in agreement with the experimental measurements.Considering the special situation of the multi-pass welding of 921A mid-thick plates, the process of pass filling is realized using "Element Birth and Death" in the ANSYS. And in view of the electrode having similar characters with the workpieces, the paper made the study simpler, taking the same thermal physical parameters in both the mid-thick plates and the weld, and this method that deals with thermal physical parameters of the electrode not only make the arithmetic simpler but also does not affect the precision of the finial results.The plat of 921A steel was eroded by electrochemical corrosion in this paper. Many factors working on the process of corrosion, the quality of etched surface and the velocity of corrosion has been taken into account. The distribution of transversal residual stress in welding material was measured using X-ray method, and the data was modified. The result indicate electrochemical corrosion is a effective method in surface residual stress test.