METHOD FOR PROCESSING HEAT-RESISTANT LOW-CARBON MARTENSITIC STEELS Russian patent published in 2023 - IPC C21D8/00 C22C38/32 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, in particular to a method for thermomechanical processing of heat-resistant low-carbon martensitic chromium steel containing 9 wt.% Cr, used in the thermal energy industry for the manufacture of equipment for thermal and gas turbines. The proposed method for thermomechanical processing of such steels will make it possible to use them for the manufacture of elements of boilers, steam pipelines, superheaters, rotors and blades of steam turbines of power plants with operating temperatures up to 630-650°C. The method includes homogenization of steel containing, wt.%: carbon 0.01, silicon 0.2, manganese 0.14, chromium 9.0, cobalt 2.85, nickel 0.08, tungsten 1.84, tantalum 0.34, titanium 0.01, nitrogen 0.016, boron 0.003, copper 2.0, sulfur 0.006, phosphorus 0.008, aluminum 0.01, iron - the rest, at a temperature of 1200°C, holding for 16 hours, cooling in air to room temperature, annealing at a temperature of 650°C for 1 h, cooling in air to room temperature. Then, rolling or forging is carried out at a temperature of 680°C to a degree of deformation of not more than 30% with obligatory heating to the specified temperature between passes with cooling in air to room temperature; isothermal annealing at 680°C for 300 h with air cooling to room temperature; tempering at a temperature of 750°C for 3 hours, followed by cooling in air to room temperature.

EFFECT: increasing the ultimate strength and creep strength of steel up to 20%, which will allow raising the operating temperature of thermal power plants to 650°C, which is 20-40°C higher compared to existing analogues.

1 cl, 2 dwg, 2 tbl