Patent GB-551018-A (GB)
Title: Improvements in or relating to the heat treatment of metal surfaces
IPC: C21D1/08
Filed: 1941-08-23
Abstract: 551,018. Heat treating metal surfaces. SHORTER PROCESS CO., Ltd., and SHORTER, A. E. Aug. 23, 1941, No. 10772. [Class 72] In the heat treatment of the surfaces of metal articles of the kind having two or more longitudinally extending surface portions displaced laterally with respect to one another, the surfaces are heated by a compound heating unit having a plurality of heating elements adapted to cover the whole of the surfaces to be treated, and relative movement is effected between the article and the heating unit in the longitudinal direction so as to bring each surface in succession under the influence of the unit, heating medium is supplied to one heating element or one set of the same so that heat is directed only on the surface in juxtaposition to the element and medium is then supplied to another element &c. when, in the course of traverse, the initial zone of a laterally displaced surface portion is brought into juxtaposition to the heating unit. As the final zone of each zone approaches its respective heating unit the supply of heating medium for that unit is turned off, and after the surfaces have'been heated they are cooled by the application of a quenching medium which may traverse cooling passages in the heating device to cool the latter. As applied to the treatment of a surface 5, Fig. 1, having the surfaces A, B, C, D which have a combined lateral width of say 10 units, a compound burner T is used having 10 jets, arranged in four groups comprising 3 jets for surface A, 4 for B, 1 for C and 2 for D. The groups of jets are connected through solenoid-operating valve mechanism A<SP>1</SP>, B<SP>1</SP>, C<SP>1</SP>, D' connected to a supply line L provided with automatic gas-regulating means R, the solenoids being operated by buttons A", B<SP>11</SP>, C<SP>11</SP>, D" connected to supply mains M. The burners may be brought into action by pressing the corresponding buttons or may be brought into operation automatically, and may be mounted on a carriage propelled in any desired manner. As applied to the treatment of track shoes 24 having surfaces SA, SB to be treated, the shoes are supported in a jig 23 immersed in liquid in a tank 16 so that only the upper surfaces are above the liquid. The surfaces are heated by burners B, B<SP>1</SP> clamped to both limbs of a bracket 31 mounted on a vertical slide 30 supported by an horizontal slide 28 carried by a bracket 27 secured to the side member 26 of an electrically-driven carriage 10 running on rails 14 at each side of the tank 16. The burners B, B<SP>1</SP> are provided with nozzles O, A connected to conduits 32, 33 and the zurner B<SP>1</SP> with nozzles O<SP>1</SP>, A' connected to conduits 34, 35, all the conduits comprising flexible tubes connected to nipples, two of which lead to the discharge ports of a dual gas supply control valve D and the other two to a similar valve D<SP>1</SP>. The supplies of oxygen and fuel being turned on, the carriage 10 is set in motion by turning on the switch 20 and as the burner heads H, H' approach the leading edges of the surfaces SA, trip 45 strikes a stop similar to the stop 46, turning on the valve D' and admitting gas to the burner B'. When the heads H, H' approach the surfaces SB, the trip 44 strikes the other stop 46, turning on the valve D and admitting gas to the burner B, and as the heads H, H' approach the trailing edges of surfaces SA, trip 45 slips off its stop, thus shutting off valve D'. In like manner, as the heads approach the trailing edges of the surfaces SB, the trip 44 slips off its stop 44, thus shutting off the valve D. During the whole of the heating operation, quenching liquid is fed by the pipe 72 and pipes 70 and not only quenches the heated surface but also cools the interior of the heads.