METHOD FOR MANUFACTURING STEEL PART Russian patent published in 1998 - IPC

FIELD: metallurgy; may be used in mechanical engineering, in particular, manufacture of valves for engines, drawing tools, punches, working members of wrenches and power tongs. SUBSTANCE: part molded from chromium-containing medium-carbon steel is subjected to thermochemical treatment in medium of gaseous nitrogen. Then, it is hardened and tempered at 510-530 C for 1.5-2 h. Part is hardened by heating in salt bath at temperature of 850-900 C and held there for 12-18 min to obtain solid solution of nitrogen and cooled under conditions preventing formation of residual austenite. EFFECT: provision for manufacturing parts from chromium-containing medium-carbon steel for service under conditions of impact-bending loads. 2 cl