METHOD OF MAKING SHARPLY BENT BRANCH PIPES BY BENDING Russian patent published in 1997 - IPC

FIELD: plastic metal working, mainly, processes for bending members of pipeline with filler by pushing them through die impression, possibly in aircraft industry, ship building and other branches of national economy. SUBSTANCE: tube blank with pressurized filler is pushed through curvilinear die impression in such a way that pressure of filler increases at pushing process according to relation q=, where q - current value of filler pressure corresponding to current bending angle β^° of blank, MPa; b, n - parameters of blank material strengthening curve σ = b•εnи

, where σ - yielding stress, ε_и - deformation intensity, r_o - outer radius of tube blank, mm; R_ср. - mean bending radius value, mm; t - thickness of tube blank, mm; μ - friction factor between blank and material of said curvilinear impression. EFFECT: enhanced efficiency. 2 dwg , 2 tbl