Pre-tension Welding And Numerical Simulation Of AL-alloy

The residual stress and distortion of thin-plate aluminum welding are the main factors that limit its wide use in industry. A new, positive and quantified method is used to control residual stress and deformation in this paper and it is named as Pre-tension Welding. By this method, the interior imbalance stresses aroused by heat effect is adjusted. The residual stress and distortion is controlled radically.A special device was designed autonomously to make 3mm aluminum thin-plate with pre-tension welding method possible. Blind-hole method was applied to measure residual stress and then gauged the deformation. Numerical simulation is used to analysis the process of welding and to predict residual stress and deformation at high pre-stress. With simulation way, experiments are reduced.After welding experiments, Pre-tension welding was proved to be an effective way to lower residual stress and distortion. With 20%σs and 50%σs applied in welding, the residual stress was reduced 33.8% and 72.9% and value of deformation was down from 12.5 to 8.9mm and 3.1mm. Simulation was optimized with experiment. The blunder of numerical simulation and experiment is less than 20% and the initial suppose is achieved. The numerical simulation way was used to predict welding process with high pre-tension and the result shows that when the pre-stress was 90%σs, it realized low stress and no distortion welding.To analysis the mechanism of Pre-tension Welding Way, some basic results are got as following: Pre-tension way can enlarge the plastic distortion region under high temperature and reduce the plastic compress strain at the same time. The plastic strain ability is enhanced during the cooling course and compressive strain remained in high temperature is offset by longitude drawing in cooling stage. The purpose to control residual stress and distortion is eventually come true.