METHOD OF THERMOMECHANICAL TREATMENT OF HEAT-RESISTANT STEEL OF MARTENSITIC CLASS Russian patent published in 2019 - IPC C21D6/00 C21D8/00 C22C38/54 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to thermomechanical treatment of heat-resistant chromium steel of martensite class, used for production of elements of boilers and steam lines, and also steam turbines of power plants with operating steam temperature up to 650 °C. To increase long-term durability, method includes homogenisation at 1,150 °C with holding for 16 hours and cooling in air to room temperature, forging at temperature of 1,150 °C with degree of deformation of 20 % and heating of workpiece between passes to 1,150 °C, cooling in air to room temperature. Heating to temperature of 1,050 °C, holding at said temperature for 2 hours, cooling in furnace to 900 °C with further holding for 1 hour, deformation by forging at temperature 900 °C with degree of deformation of 80 % with workpiece heating up to 900 °C between passes, isothermal annealing at deformation temperature for 3 hours with subsequent cooling in air to room temperature, tempering at 770 °C is cured for 3 hours and cooled in air to room temperature.

EFFECT: increased index of long-term strength.

1 cl, 2 tbl, 2 dwg