GB843395A - Improvements in or relating to the heat treatment of metal parts - Google Patents

Abstract

843,395. Annealing furnaces. HEDIN Ltd. Jan. 2, 1958 [Oct. 2, 1956], No. 30011/56. Class 72 [Also in Group XII] Metal articles are quenched in the furnace in which they have been heated by introducing a cooling liquid into the furnace when the heating operation is completed. As shown, the furnace 1 comprises insulating walls containing refractory members 5 which project into heating chamber 6 and support electric heating elements 7. Container 8 is supported on a ring 9 of refractory material and is provided with a central aperture 10 for the entry of the quenching liquid. A diffuser consists of a metal plate 11 supported on a ring of perforated material 12 and a perforated plate 13 which serve to deflect water entering by aperture 10 through the holes in ring 12 which then rises evenly up the container through the perforations in plate 13. This plate also supports a basket 15 which contains the articles being treated. A lid 16 has its edges sealed by means of the downturned lip 17 engaging sealing material. To operate the apparatus a loaded basket 15 is set in place, the lid sealed, and control valve 26 is adjusted to allow a small flow of water through auxiliary heater 27 and inlet pipe 23, into container 8 where it is volatilized by the heat to form a protective atmosphere. Valves 24 and 28 are closed during heating. To quench, valve 24 is opened and water flows into container 8 overflowing through pipe 29 bypassing steam vent 30. After quenching the container 8 is drained by means of valve 28 and, after the removal of the lid, the basket is raised by means of winch 20.