METHOD OF MANUFACTURING HARDENED STEEL ARTICLES WITH ACCURATE GEOMETRICAL DIMENSIONS Russian patent published in 2014 - IPC C21D9/40 

FIELD: machine building.

SUBSTANCE: articles are installed with a gap into austenitic stainless steel tubes which are rigidly fixed by a non-detachable connection in the base of a device and are free to elongate and expand at heating, the device with articles is put into a cooling vessel, the vessel is blown through by inert gas under excessive pressure to provide for non-oxidising environment, the vessel is connected to a muffle with inert gas blowing being continued, the device with articles is installed in the preheated space of the furnace muffle. Movement of the device with articles, their heating up to the hardening temperature and maturing are carried out in the inert gas environment under the pressure exceeding the atmospheric one, after heating the device with articles is placed in the cooling vessel, the vessel is disconnected from the furnace muffle and cooled under the pressure exceeding the atmospheric one down to the temperature of not more than 100°C and then the device with articles is unloaded.

EFFECT: provision for required straightness of articles.

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