GB894737A - Method of producing metal tubes, particularly steel tubes in an extrusion press - Google Patents

Abstract

894,737. Extruding; billet piercing. HYDRAULIK G.m.b.H. June 16, 1960 [Aug. 14, 1959], No. 21266/60. Class 83 (4). A metal tube 12, particularly of steel, is made by backwardly extruding a billet 2 between a mandrel 3 and a die 10 carried by a moving hollow ram 7, the mandrel being gradually withdrawn as the die moves forwardly. The ram 7 is mounted on a crosshead 8 driven by a piston and cylinder 9, 11. During the extrusion stroke of the ram, mandrel 3 is withdrawn to the left by a retraction cylinder 5 connected by conduit 6 to a cylinder in the cross-head 8. An adjustable throttle valve in the conduit controls the rate of withdrawal. Alternatively, the mandrel may be withdrawn by pressure fluid supplied from pumps or a pressure accumulator or it may be withdrawn mechanically. Hollow billets 2 may be used or solid billets may be pierced by the mandrel driven by means 4. A backing plate 14 for the container 1 has a dove-tail groove 15 into which the end of the billet is pressed during extrusion. Thereafter the container 1 is moved to the right by piston 16 and the extruded tube is sawn or shorn from the discard retained in the groove 15.