METHOD OF CYCLIC GAS NITRATION OF STEEL DIES FOR HOT FORMING Russian patent published in 2014 - IPC C23C8/26 C23C8/34 B82Y30/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, particularly, to chemical-thermal processing, in particular to cyclic gas nitration of alloys steels with application of nanotechnologies, and can be used for production steel dies for hot forming to be used at high temperatures. Heating is performed in the temperature range of T=550-590°C. Then, alternate feed of air and ammonia at air feed interval larger than that of ammonia in a cycle and with formation of water steam. Oxide films are produced at die surfaces and have electric charge to allow formation of the structure that consists of iron nitride nanoparticle ply and monolith play of cermet as oxycarbonitride. Then, curing is performed follows by cooling together with furnace. In particular cases, cycle interval makes 50 s at furnace volume making 0.5 l.

EFFECT: higher heat conductivity of die surface, deterioration and heat resistance.

2 cl, 1 tbl, 2 dwg, 6 ex