GB751506A - Thermochemical metal removal - Google Patents

Abstract

751,506. Removing surface metal by blowpipes. UNION CARBIDE & CARBON CORPORATION. Feb. 8, 1954 [March 18, 1953], No. 3690/54. Class 83 (4). Stainless steel bodies containing up to 20 per cent chromium and up to 15 per cent nickel which are resistant to conventional flamedesurfacing operations are desurfaced at rolling temperatures and speeds by applying a plurality of pre-heating flames to a surface portion of the body, discharging a relatively flat stream of oxidizing gas at an acute angle against the resulting heated portion and discharging a powdered solid fuel into the oxidizing gas stream, the solid fuel stream having additional gas introduced under pressure to increase its velocity and thus being discharged from a series of uniformly spaced openings to form a series of powder streams mixing to form a wide powder-gas stream. The scarfing head has a series of nozzles 14 each having a flat orifice 41 for emitting oxygen under pressure as a flat stream 20. Reheating gas flames 22 and 24 are produced from ports 16, 18. Powdered fuel is projected from a powder nozzle 10 with uniformly spaced slots 39 directing the powder in a flat stream 40. Each of the slots 39 is connected via a tube 42 to a powder distributer 44 connected in turn to a powder-laden gas supply line 45. Powder is supplied by a standard dispenser 50 through a valve 48 and boosters 46, 47 prevent settlement of the powder and increase the velocity of the powdergas streams. These work on the injector principle. The powder nozzle may have round outlets. The oxygen nozzle may be continuous instead of being in the form of spaced nozzles 41. A flat stream of water 59 is discharged from a nozzle 58 ahead of the scarfing flame to remove slag and scale.