GB564012A - Method of and means for hardening internal surface portions of metal articles - Google Patents

Abstract

564,012. Hardening metal articles. SHORTER PROCESS CO., Ltd., and SHORTER, A. E. May 21, 1943, No. 8085. [Class 72] In the hardening of the internal surface portion of a metal article, a heat transfer shaped in conformity with the surface portion is placed in contact with the latter and high temperature heat is directed on the exposed surface of the member to raise it to the critical temperature by conduction through the member, the heated surface being then quenched either before or after the member is removed. As applied to the hardening of the surface S of the recess R in an article W, a closely-fitting plug P, Fig. 2, of heat-conductive material, such as carbon, is inserted in the recess and high temperature heat from a burner N is directed on to the exposed face of the plug P. At the end of the heating period the gas supply to the burner N is turned off and a supply of quenching fluid to the annular quenching head Q is turned on. If a surface having maximum hardness is required, the plug P may be ejected simultaneously with the cessation of heating, so that the fluid is directed on to the heated surface of the recess R. In the treatment of deep seated recesses such as die blocks, heat conductive material P in the plastic condition is inserted in the recess and allowed to harden. A shallow depression D may be formed in the material P into which the tip of the nozzle N of the burner B is introduced. When the surface S has attained the critical temperature, a quenching fluid is directed on to the heated block and at the same time the mass P may be gouged out of the recess. In a machine for carrying out the hardening, shown in Fig. 4, the article W is mounted in a holder H comprising a chuck 12 in which the work is retained by spring- pressed balls 13, and secured to one end of a hollow shaft 14 mounted in bearings 15, 16 carried by a base 10 and rotated by a motor M. Extending through the shaft 14 is an ejector pin 21, for ejecting the plug P from the work W on the termination of the heating period and an ejector sleeve 22 for ejecting the work W from the chuck 12 upon completion of the quenching operation. The pin 21 projects beyond the sleeve 22 guided by a bracket 23 and is coupled through a thrust member 24 and a link 25 to a lever 26 pivotally mounted on a block 27. The lever 26 is coupled to the sleeve 22 by a link bar 28 having a slot 29 engaged by a pin 30 on a crank 31 pivotally mounted on a block 32 and engaging a collar 33 on the sleeve 22. The ejecting mechanism is held in the position shown with the lever 26 abutting against a stop 34 by a spring 35 bearing against a bracket on the sleeve 22 and a cupped flange 36 on the pin 21. The burner B and quenching nozzle Q are carried by a clamp C secured to a slide 37 carried by a bed 38 on the base-plate 10 and held in position by a spring-controlled detent 41 controlled by a spring 42 and operated by a link 43 from a pedal 44. The slide 37 is propelled when released by the operation of the detent 41 by the pedal 44 by means of a spring from the position where the plug is heated by the burner B to another position where the quenching nozzle Q is in line with the plug. The supply of the heating and quenching media may be controlled by means of solenoid-operated valves connected to relays to trip switches associated with the clamp C and operable, upon movement of the slide 37, to turn on and off the supply of the media in the appropriate sequences.