GB603446A - Method of and apparatus for heat-treating thin metal work-pieces - Google Patents

Abstract

603,446. Automatic control of temperature. AIR REDUCTION CO., Inc. June 7, 1945, No. 14442. Convention date, June 14, 1944. [Class 38 (iv)] [Also in Groups II and XL (b)] Thin work-pieces, e.g. pipes or tubes, of a ferrous metal that is hardenable by heating and quenching are heat treated by directing heating flames against one surface of the workpiece to heat the metal above its critical temperature, effecting relative movement behind the flames and the work piece so that the latter is heated progressively, quickly quenching the heated metal by projecting fluid against the opposite surface of the work piece and adjusting the rate of relative movement between the flames and the work piece in accordance with the heat condition of the metal existing at the opposite side of the work-piece. As applied to the heat treatment of a pipe 12, the latter supported on a roller 11 is moved progressively past a torch or heating unit 14 having spaced openings 15 which direct a ring of flame against the inner surface 16 of the tube, by pairs of rollers 21 fitting the pipe and driven by shaft 22 from a shaft 23 having inner gears 24, 25 and driven by a motor 26 having a field winding 27. The latter is connected by wires 32 to an automatic control device 31 which maybe a heat or light sensitive current controller of known type and is responsive to heat energy radiated from the pipe 12. A cooling ring 35 supplied with fluid from a pipe 38 prevents the spread of heat rearwardly along the pipe and a quenching pipe 36 supplied from a pipe 37 is provided for cooling the heated part of the pipe after it has passed the device 31.