METHOD OF CARBONITRIDING PARTS MADE FROM STRUCTURAL AND TOOL STEELS Russian patent published in 2016 - IPC C23C8/76 

FIELD: construction.

SUBSTANCE: invention relates to a method of carbonitriding parts from structural or tool steel and can be used for surface strengthening of parts of machines and tools in machine building, metallurgy, chemical and tool industry. Method includes production of paste by mixing of potassium ferricyanide K₄Fe(CN)₆ and gaseous soot DG-100, applying paste onto an article, heating with holding, cooling in oil and low-temperature tempering. Paste preparation includes further addition of barium carbonate, bentonite, marshalite and paste-forming liquid in form of polyvinyl acetate emulsion in following proportions, wt%: potassium ferricyanide K₄Fe(CN)₆ - 16-20, barium carbonate BaCO₃ - 14-18, bentonite - 12, marshallite - 24, gaseous soot DG-100 - balance, paste-forming liquid, vol%: polyvinyl acetate emulsion - 50, ethanol - 10, water - 40. Method includes heating in neutral salt bath at following ratio of components, wt%: NaCl - 50, Na₂CO₃ - 50 at temperature of 750-950 °C with holding at said temperature for 1.0-6.0 hours, after which samples are cooled in oil and low-temperature tempering at temperature 150-200 °C.

EFFECT: higher speed carbonitriding and reduction of labour intensity of said process, wider temperature range, high uniformity of heating of steel parts and environmental safety.

1 cl, 1 ex