Wall thickness variation of 1Cr18Ni9Ti stainless steel integral elbow with small reative bending radius during hydroforming
Aiming at the urgent demand of aerospace equipment for integral manufacturing technology of stainless steel elbow with large diameter to thickness ratio(D/t>60)and small relative bending radius(R/D<1),and the technical problem that traditional process can not be integral forming,a two-step forming process method of push-bending and hydroforming of tube fittings was proposed.The relation-ship between the size of the tube billet and the integral elbow was deduced theoretically,and the change law of the wall thickness of the in-tegral elbow during the two-step forming process was analyzed by finite element simulation.It is found that the outer wall of the integral el-bow decreases and the inner wall thickens after push-bending.Die clearance and friction factor are the main factors affecting the change of push-bending wall thickness.Too small clearance or too large friction force can aggravate the thinning of outer wall and the thickening of inner wall.During hydroforming,the outer wall of the integral elbow is pasted first,and the round corner area of the inner wall is pasted later.The inner and outer walls of the integral elbow are thinning,and the greatest thinning is located in the center area of the outer wall.The 1Cr18Ni9Ti stainless steel integral elbow with diameter of Φ200 mm,diameter to thickness ratio of 67 and relative bending radius of 0.76 is formed.The wall thickness distribution is uniform.
elbow with thin wall and small radiuspush-bendinghydroformingFEM simulation
万方数据
维普
