PIPE PRESSING METHOD AND APPARATUS Russian patent published in 1997 - IPC

FIELD: plastic working of metals, in particular, production of pipe on presses operating without piercing system. SUBSTANCE: method involves mounting centering sleeve in die; positioning mandrel into central opening of billet; placing billet in container of press; mounting washer; centering rear end of mandrel in pressing washer and front end in centering mandrel; pressing pipe into gap between mandrel and die. Apparatus has container, die, pressing washer, process washer, loose detachable connection and movable mandrel with stepped shank and centering sleeve. Stepped shank has cylindrical step of predetermined diameter and cylindrical rear end. Front and rear ends of mandrel are beveled. Spring is positioned adjacent to working part of mandrel. Centering sleeve is made in the form of conical spring with regulated diameters. Front end of pressing washer has annular concave portion. Curvature of this portion depends on that of die opening. End surface of process washer adjoining to pressing washer is equally spaced from curved portion, which is provided with variable section channels having regulated depth. Detachable connection may be formed as sleeve for loose joining of pressing washer with movable punch. Contacting surfaces of pressing washer and punch are made spherical. Die is rigidly fixed in immovable container. Detachable connection may be formed as ring adapted to connect die with immovable hollow punch. Pressing washer is fixed in movable container. EFFECT: increased efficiency, simplified method and construction and improved quality of pipes. 6 cl