METHOD FOR PRODUCING HIGH-STRENGTH THIN-WALL STEEL ARTICLES WITH ACCURATE GEOMETRY SIZES Russian patent published in 2007 - IPC C21D9/40 

FIELD: machine engineering, namely heat treatment of articles of maraging steels.

SUBSTANCE: articles of maraging steel are placed with gap in strut having n-number of mandrels of austenite steel. Said strut is placed in tank for cooling and inert gas is blown through it such as argon under excess pressure. Tank is connected with muffle of furnace while argon blowing through is going on. Then strut with mandrels is moved to heated zone of muffle and it is placed concentrically relative cylindrical surface of muffle. Articles on mandrels are moved, heated and soaked in argon atmosphere under pressure exceeding atmospheric one. In order to provide accelerated cooling outside heating zone, strut is again moved to cooling tank and cooling process is realized without disconnection of tank from muffle under argon pressure exceeding atmospheric pressure. Or tank is disconnected from muffle for further setting up pressure in cooling tank higher than atmospheric pressure. Then articles are discharged into air at temperature of mandrels no more than 150°C. Heating, soaking and cooling stages are realized under pressure no less than 50 mm of water column.

EFFECT: stable geometry sizes, desired level of mechanical properties of articles.

4 cl