METHOD FOR GAS NITRATION OF PRODUCTS OF STRUCTURAL STEELS Russian patent published in 2017 - IPC C23C12/02 C23C8/36 C23C10/36 

FIELD: metallurgy.

SUBSTANCE: method for chemical-thermal treatment of products of structural steels includes heating in furnace in product reactor in nitrogen-containing atmosphere, isothermal holding in nitrogen-containing gas flow, and subsequent cooling with furnace. The heating is carried out in the reactor in the presence of a filler as a catalyst to create a layer of active particles around the products by means of nitrogen-containing gas flow. Simultaneously, the zinc impregnation process is performed using powdered zinc as a filler in a mixture with quartz sand and providing a layer of active particles consisting of nitrogen and zinc-containing substances around the products. In particular embodiments of the invention, heating, isotheric exposure and cooling of products is carried out in dissociated ammonia atmosphere. Isothermal holding is carried out in the temperature range of 750…850°C. Powdered zinc and quartz sand in the filler comprise a ratio of 1 to 10.

EFFECT: increase of corrosion resistance while providing thicker reinforced layer and sufficient strength.

4 cl, 5 dwg, 1 tbl