锥形模, 机械扩径, 扩径力, 主应力法

Mechanical expanding of tube with conical die was investigated, stress state of unit in deformation zone was analyzed, unit model of deformation zone was established, slab method to solve deforming force on metal plastic forming was adopted, according to Mises yield criterion, considering effects of work hardening and bending stress, analytic formula of the mechanical expanding was derived. Moreover, the formula was amended by taking account of effect of fixing-diameter zone.The amended formula indicate that expanding force is related to die semi-cone angle, friction coefficient between die and tube internal surface, original diameter of tube, tube thickness, expanding coefficient and length of die’s fixing-diameter district. The rationality and correctness of expanding force formula were proved by expanding tests.