【摘要】 为解决传统技术无法制造大径厚比、小弯曲半径铝合金薄壁弯管的难题,提出采用双层管充液弯曲新方法。运用数值模拟研究厚度比和内压对低碳钢/铝合金双层管充液弯曲过程中起皱行为和壁厚分布的影响。结果表明,随着厚度比的增加,起皱的现象得到缓解直至消除,内层弯管外侧减薄率逐渐减小,壁厚分布更为均匀;随着内压的增加,起皱现象逐渐延缓,内层管壁厚最大减薄率增加,因此增加厚度比和内压均有助于提高双层管弯曲成形的稳定性。通过实验成功研制出径厚比为63的铝合金薄壁弯管件,外侧最大减薄率为24%。更多还原

【Abstract】 Hydroforming process of double-layered tube is proposed to solve the wrinkling encountered in manufacturing the ultra thin elbows with traditional bending processes.The numerical simulation of hydroforming of carbon steel/aluminium alloy doublelayered tubes were conducted to investigate the influences of internal pressure and thickness ratio on wrinkling and wall thickness distribution of the double-layered tube.It is shown that the maximum wall thinning of the outer elbow decreases and the wrinkling eliminates as the thickness ratio increases,which implies a uniform wall thickness distribution.With inner pressure increases,the inner thinning rate decrease gradually,and the wrinkling was delayed.So increase thickness ratio and pressure are helpful to improve the stability of double-layered tube.The hydro-bending experiments are carried out to obtain successfully the thinwalled elbow tubes with bending angle is 70°.The outer maximum thinning rate was 24%.Results proved that double-layered tubes hydroforming is suitable for manufacturing large diameter-thick ratio of ultra thin-walled tube.更多还原