METHOD FOR PRODUCTION OF STRENGTHENED STEEL PRODUCTS OF ACCURATE GEOMETRIC DIMENSIONS AND SHAFT RESISTANCE FURNACE FOR ITS REALISATION Russian patent published in 2009 - IPC C21D9/40 C21D1/76 F27B1/09 F27B5/04 

FIELD: technological processes.

SUBSTANCE: invention is related to the field of thermal treatment of products from stainless steels of martensite grade. To protect surface of products against oxidation, to increase efficiency of furnace, accessory with products is placed in reservoir for cooling, reservoir is blown with inertial gas at excessive pressure, reservoir is connected to muffle, continuing blowdown with inertial gas, then products are displaced into previously heated muffle, heated up to temperature of tempering, maintained in medium of inertial gas at pressure higher than atmospheric, and after heating accelerated cooling is carried out in reservoir for cooling, at the same time cooling is carried out without disconnection of reservoir from muffle at pressure that exceeds atmospheric or by its disconnection from muffle with maintenance of pressure above atmospheric until the moment of products unloading from reservoir for cooling, and products are unloaded in air at temperature of not higher than 200°C. Furnace comprises jacket, lining, heaters, muffle arranged as open in lower part, cover, adapter with gate, tubes for inertial gas entry into working space and exit from it, reservoir with water jacket and with cooling medium for cooling of products heated in muffle, which is tightly connected to lower part of muffle through adapter device, at the same time reservoir for cooling is equipped with gate arranged in point of connector with adapter device and providing for excessive pressure of inertial gas in reservoir for cooling during its disconnection from muffle.

EFFECT: protection of product surface against oxidation.

2 cl, 1 dwg