Patent GB-363376-A (GB)
Title: Improvements in the treatment of steel and other ferrous alloys
IPC: C21D1/04
Filed: 1930-08-06
Abstract: 363,376. Treating steel and steel alloys. SOC. D'EXPLOITATION DES PROC•D•S MAHOUX, 62, Avenue de la Republique, Paris.-(Assignees of Mahoux, A. P. and Mahoux, G.; 7 bis, Rue d'Asnieres, La Garenne, Seine, France.) Aug. 6, 1930, No. 23557. Convention date, Nov. 18, 1929. [Classes 72 and 82 (i).] The physical characteristics of steel and alloys thereof are modified by producing in the steel &c. mechanical vibrations of ultraaudible frequency. the steel &c. being heated to a temperature below the lowest critical temperature. Electromagnetic oscillations may also be produced in the steel &c. By carrying out the process in the presence of a gaseous hardening agent such as carbon or nitrogen, surface hardening of the steel is also produced. The mechanical vibrations may be produced electrically or mechanically. In the apparatus shown in Fig. 1 in which the vibrations are produced electrically and surface hardening of the steel is effected, the steel &c. piece 5 is connected by a rod 6 to a metallic disc 11 which is secured to a tube 12 of insulating material in which is mounted an induction coil 13 connected at its upper end by a wire 20 to an electric oscillator 21. The coil 13 is connected at its other end to a lead 14 provided with a switch 15 by which it may be connected with an earthed wire 16 or a wire 17 attached to the piece 5. The piece 5 is mounted within a receptacle 4 supported on an insulated plate within an electric furnace 1, inlet and outlet pipes 8, 9 being provided for the gaseous hardening agent. A metallic sleeve 10 inside the receptacle 4 distributes the hardening agent round the piece 5. When the piece 5 has been heated to the proper temperature, the oscillator 21 is set in operation. The high-frequency current flows through the coil 13, wire 14, switch 15, to earth through wire 16. The coil 13 acts on the plate 11 and produces the mechanical vibrations which are transmitted to the piece 5. If surface hardening is desired, a current of gas is circulated by the pipes 8, 9 through the receptacle 4. To produce electromagnetic oscillations as well as mechanical vibrations in the piece 5, the current by the switch 15 and wire 17 is sent through the piece 5, the condenser formed by the piece 5 and the tube 10 and then to earth through the pipe 9 and wire 19. In a modification, the coil 13 is substituted by a condenser one plate of which is attached to the rod 6. In the apparatus shown in Fig. 3 for producing the vibrations mechanically, a stationary disc consisting of members 34, 34a, is secured to a shaft 35 mounted on a rubber lining 37 in a frame 36. The member 6, to which the piece is connected, is fixed to a member 38 secured to the end of the shaft 35. Nozzles 40 on the part 34a open into a chamber 41 connected by a pipe 42 and a radial conduit 43 to a pipe 44 through which air or other gas under pressure is supplied. Opposite the plate 34a is arranged a toothed disc 45 which is mounted on a frame 46 and rotated at high speed. The nozzles 40 blow air &c. alternately on the teeth of the wheel 45 and the gaps between the teeth and this results in the production in the parts 34, 34a of mechanical vibrations which are communicated through the members 38, 6 to the piece under treatment. An alloy steel referred to contains À35 per cent of carbon, 2À9 per cent of chromium, 3À5 per cent of nickel, and 0À5 per cent of molybdenum. Specification 360,833 is referred to.