GB1092717A - Plant and process for producing seamless tubes using a push-bench, and seamless tubes produced by the process - Google Patents

Abstract

1,092,717. Rolling tubes. TUBE MILL HOLDING S.A. Nov. 18, 1965 [Nov. 18, 1964], No. 46986/64. Heading B3M. Seamless tubes are produced by passing a square billet down skids 34, Fig. 12, into a rotating hearth furnace 35, turning the hot billet through 180 degrees by a device 36, passing the billet to a combined centering and sizing press 37, where the front centre hole is filled with a scale preventing flux, and thence to a combined press-piercing and rolling mill 44, the bloom then rolls down a table 45 on to the rotating table 46 of an upsetter 47; the bloom passes on to the table 49 of a push bench 50 wherein a mandrel 51 pushes the hollow bloom through reduction rolls, and finally the rolled tube is loosened by cross rolling in a reeler 53, and freed from mandrel 51 by an extractor 54. The upsetter comprises a pusher ram 3, Fig. 1, actuated by two double-acting pressure cylinders 4, a mandrel 5 actuated by a doubleacting pressure cylinder 6, and a roll stand 7 having four grooved rollers 8. In operation, ram 3 pushes bloom 2 into rolls 8 which sink the end of the bloom, Fig. 2. Ram 3 is stopped, and mandrel 5 is moved axially until it engages the shoulder in the bloom bore. The ram 3 and mandrel 5 advance simultaneously and at the same speed until the bloom reaches a stop 11, at which stage the required upset has been provided on the end of the bloom. In a modification, the upsetter of Fig. 6 provides a pusher ram 3 with a nose portion 15; a stripper plate 20, and idler roller dies are provided, and stop 11 is omitted. In a further modification the upsetter of Fig. 9 has three roller die stands 23, 24, 25, and the rolls are all driven by a common motor 31. The upsetter of Fig. 13 has a mandrel 5<SP>1</SP> which has a tapered end; the rolls 8, 18, 19 are idle rolls.