METHOD FOR HARDENING PARTS MADE OF TOOL AND STRUCTURAL STEELS IN CARBURIZED ENVIRONMENT Russian patent published in 2021 - IPC C23C8/66 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, in particular to chemical-thermal treatment of structural and tool steels, and can be used for surface hardening of machine parts and technological equipment in machine-building, metallurgical, chemical, tooling and other industries. A paste is prepared containing the following components, wt.%: barium carbonate ВаСО₃ - 20-30, ferrochrome PhH800А - 15-20, ammonium chloride NH₄Cl - 2-4, bentonite 5-10, marshalite - 10-20, soot DG-100 - the rest. As a pasting agent, nitrocellulose varnish NC222- 20-30% is used of the mass of powder components. The paste is applied to the part, then it is dried at a temperature of 70-80°C. Then the part is heated in a neutral salt bath at the following ratio of components, wt.%: NaCl - 35, Na2CO3 - 35, NaOH - 30, at a temperature of 580-680°C with holding at this temperature for 2-6 hours. Heating is carried out in a neutral salt bath at the following ratio of components, wt.%: NaCl - 50, Na2CO3 - 50 at a temperature of 950-1150°C for 2-4 hours. Then the part is subjected to quenching and tempering at a temperature of 200-550°C for 2 hours.

EFFECT: invention provides an increase in the strength of the coating, wear resistance and corrosion resistance of parts, as well as the possibility of processing parts of any size and shape and the possibility of local strengthening of the working surfaces of parts.

1 cl, 1 ex