GB1426314A - Method of making a metallic simifinished product - Google Patents

Abstract

1426314 Making metallic semi-finished products; welding by pressure; continuous casting OLSSON INTERNATIONAL Inc 25 Feb 1974 [5 March 1973] 8526/74 Headings B3A B3R and B3F A method of making a metallic semi-finished product comprises, continuously solidifying a layer of molten metal on the surface of a rotating chilled roll, an endless belt or a succession of mould elements which has its lower portion immersed in molten metal 8 in a vessel 2, the layer being of a thickness less than that of the semi-finished product, stripping the layer from the roll &c. and either deforming the layer so that portions of the layer are immediately adjacent one another and pressing the portions together or pressing a plurality of simultaneously formed layers 10, 12, 15 together, the pressing operation fuse-welding the portions or the layers 10, 12, 15 together at a solidus temperature at which the metal has insufficient plastic strength for normal hot rolling but where liquid metal is not visible. On one or more rollers a number of narrow strands may be formed sideby-side to be fused together subsequently. As shown, the molten metal is discharged from a ladle 3 and maintained at a constant level in the vessel. A plurality of rollers 5 are partially immersed in the molten metal and strippers 11, 14, 18 remove the solidified layers of metal off of each one. Release material is applied to each roll surface by means 21 and as the molten metal rises through a false bottom 23 in the vessel 2 baffles 24 keep slag or other surface impurities away from the rolls 5. The layers 10, 13 are fuse-welded by a roller 13 and the combined layers are welded to the layer 15 by a roller 16. The strip so formed passes through a guide 19, which is an extension of a hood 9, and when it is at the required rolling temperature it is passed through reducing rolls 25. Inert or non-oxidizing gas is supplied to the hood and the guide 19 restricts escape of the gas. A single strip only may be formed and it is folded over longitudinally until the required thickness is obtained, Figs, 3-6 (not shown), or it may be rolled longitudinally and welded into a coil to form a tube or rod, Fig. 7 (not shown). Two rolls, each dipping into molten metal may produce separate layers to be pressurewelded in the pals. In a further embodiment a single corrugated roller (30) is used. Fig. 2 (not shown), and the corrugated layer (32) is compressed into bar form (35) between rolls (34). The fuse-welding of the layers, which are preferably 5-12 mm. thick in the case of a killed steel, prior to reduction rolling ensures that the majority of the metal is from the chill zone whereby its composition conforms closely to that of the molten metal and its mechanical proportion are superior to those of metal which has solidified slower.