METHOD AND DIE FOR FORMING STEEP-CURVED BRANCH PIPES Russian patent published in 1995 - IPC

FIELD: plastic working of metals. SUBSTANCE: method involves placing tubular billet with resilient filler into die having curved channel conforming to branch pipe to be manufactured, straight channel intersecting curved channel at right angle and cavities in the form of spherical segments adjoining to curved channel proximate elbow portion of minimum radius. In the process of axial setting filler is compressed to expand billet from inside. Additional bulging surfaces proximate elbow portion of minimum radius of branch pipe are formed to obtain part with equal length of generatrix in longitudinal section without formation of wrinkles, corrugations and thickened portions in ready branch pipe. Additional bulging portions on formed part are cut at their end sides to obtain steep-curved branch pipe. EFFECT: increased efficiency and improved quality of parts. 3 cl, 1 dwg