LOW STRESS NON-DISTORTION(LSND) WELDING——A NEW TECHNIQUE FOR THIN MATERIALS

Low Stress Non-Distortion(LSND) welding is a new technique for inprocess active control of welding stress and distortion during the manufacturing of thin walled structural elements.The method involves creating a specific uneven temperature distribution on the workpiece.Restraining forces are applied to the workpiece in order to prevent the out-of-plane buckling which is caused by both the heating and welding operation.Therefore,an induced "streching effect" which follows the welding heat source,controls quantitatively the formation of incompatible compressive plastic strain and thermal stress or,alternatively,redistributes the residual stress field across the workpiece.In this way,the low stress non-distortion results can be achieved using the same parameters as in the conventional welding methods.