METHOD FOR ECOLOGICALLY CLEAN CARBURIZING OF METAL PARTS Russian patent published in 1995 - IPC

FIELD: metallurgy. SUBSTANCE: method for ecologically clean carburizing of metal parts includes production of endothermal controlled atmosphere by catalytic conversion of hydrocarbon gas with oxidizer (air) and supply it to carburizing space with addition of hydrocarbon has C_nH_2n+2 in the amount of (1-5)100n of volume of supplied atmosphere. Used atmosphere is discharged from carburizing space through hermetic line and together with additional amount of hydrocarbon gas and oxidizer is returned for conversion. Increase of hydrogen content in used atmosphere is compensated by replacing part of oxidizer with carbon dioxide in the amount of (0.8-1.1)nN of volume of added hydrocarbon gas where N is return factor expressed by ratio of volumes of atmosphere removed from carburizing space and that of supplied to it. EFFECT: higher efficiency. 1 tbl