METHOD FOR MAKING SINGLE-CORRUGATION BELLOWS Russian patent published in 2002 - IPC

FIELD: manufacture of single-corrugation bellows with cylindrical shells. SUBSTANCE: method is realized by performing radial shaping of corrugation of tubular blank and upsetting blank in lower die while applying inner pressure. Method comprises step of preliminarily determining total measured volume of working liquid in cavity of tubular blank and maximum pressure value at radial shaping realized by supplying working liquid to cavity of tubular blank restricting inner sealed space of lower die; performing axial upsetting in die at sustaining inner pressure that is less by (3-6)% than maximum pressure of working liquid inside inner space at radial shaping; additionally supplying total measured volume of working liquid and removing air remaining in lower die or realizing radial shaping and axial upsetting by two stages. At first stage radial shaping of corrugation is realized by supplying part of total volume of working liquid consisting (60-70)% of its value and performing axial upsetting only by (30-40)%. At second stage radial shaping is realized by supplying remaining volume of working liquid and completing axial upsetting. EFFECT: enhanced quality of single-corrugation bellows with cylindrical shells operating at high temperature and pressure values. 3 cl, 3 dwg