Experimental and numerical investigation of fixture time on distortion of welded part

Abstract

In this paper, the effect of clamping time on welding distortion is studied. The welding process has been done in austenitic stainless steel 304L butt-welded joint by TIG welding method. The numerical thermo-mechanical analysis is performed using commercial finite element software ABAQUS. The welding simulation is performed using the birth and death of elements technique. The heat source model that used in this study is the Goldak double-ellipsoidal model. At last, for verifying numerical results, a set of experimental tests have been carried out and welding distortion has been measured. The experimental measured data are compared with numerical (FEM) results. The results showed that the clamping causes change in direction of bending and angular distortions (opposite of without clamping mode). Any increase in clamping time relatively causes a decrease in angular and bending distortions. A 70% reduction of angular and bending distortions were observed in cold release mode (unclamping after the workpiece has cooled down to room temperature) compared with hot release mode (an immediate unclamping after welding). The position of clamping has a significant effect on distortion reduction as well. If clamping position is moved closer to the weld line, the distortion is decreased. By reducing relative clamping distance of 60 to 20 mm, the angular distortion is reduced to 0.15 mm which is about 25% and bending distortion of 0.6 mm (40%) can be achieved. The angular and bending distortions are increased when the sheet width is reduced during the experiments. It should be noted that the measured results of experiments and numerical method are in a relatively good agreement and the amount of error is within the acceptable limits.