METHOD AND HYDRAULIC PRESS FOR HOT EXTRUSION OF HOLLOW PRODUCTS AT ACTIVE ACTION OF FRICTION FORCES Russian patent published in 1998 - IPC

FIELD: plastic metal working, namely hot extrusion of hollow products widely used in aircraft construction, chemical machine engineering, ship making and so on. SUBSTANCE: method comprises steps of heating hollow blank, placing it in sleeve of container into which through cavity of said blank needle is passed; extruding blank by means of short extrusion ram through annular gap restricted by die hole and said needle and determining shape and dimension of ready product; at extrusion process sustaining ratio of container motion speed Vc to motion speed Vr of short extrusion ram equal to 1.01 -1.4, ratio of needle motion speed Vm to Vr equal to 1.01 -1.05, ratio of Vc to Vm equal to 1.02-1.33. Hydraulic extrusion press includes frame, front and rear cross pieces, container mounted with possibility of reciprocation motion. Power cylinder of press is stationary secured to said rear cross piece. Main traverse bar and plunger secured to it are joined with additional cylinder supporting said short extrusion ram. Hollow long extrusion ram is mounted on front cross piece coaxially relative to said short ram. In cavity of said short ram needle with needle holder are arranged. Press is also provided with flanged broach. EFFECT: enhanced efficiency of method, improved design of press. 25 cl, 8 dwg