核级304不锈钢超薄壁三通液压胀形模拟及实验

Hydroforming simulation and experiment on SS 304 thin-walled T-shapes

对304不锈钢超薄壁三通的液压成形工艺过程进行有限元模拟,研究液压成形过程中冲头挤压速度、内压和圆角半径对成形结果的影响规律。结果表明,支管顶部壁厚值最小,主管端部以及过渡圆角半径处壁厚值最大;随着挤压速度的增大,三通支管高度先增加后逐渐减小;内压不足容易导致起皱,内压过大则支管顶部严重减薄甚至开裂;随着过渡圆角半径的增加,最大支管高度明显增加,壁厚均匀性改善。实验结果表明,成形内压和轴向进给速度匹配较为合理时,可以成形得到既不起皱也不开裂的不锈钢超薄壁三通管件。

The effects of punch velocity,internal pressure and fillet radius on the hydroforming results were studied with the FE method for SS304thin-walled T-shapes.The simulation results showed that,the top part of the branch obtained the minimum wall thickness,while the ends of the main pipe and transition fillets area had the maximum wall thickness.With the increase of the axial velocity,the height of branch pipe increased at first,then decreased gradually.Insufficient internal pressure easily resulted in wrinkles,but too high internal pressure led to severely thinning or even cracks at the top of branch.With the increase of transition fillet radius,the maximum height of the branch pipe increased evidently and the uniformity of wall thickness was improved.The experimental results demonstrated that thin-walled T-shapes without any wrinkles or cracks could be fabricated by suitable match of processing parameters especially internal pressure and axial feed velocity.