METHOD FOR PRODUCING STEEL PART WITH LOCALLY SOFTENED PART Russian patent published in 2023 - IPC C21D8/00 C21D1/18 B21D22/26 B21J1/02 B21J5/00 C22C38/06 C22C38/38 

FIELD: metallurgy.

SUBSTANCE: invention is related to production of a steel part having a locally softened part, and can be used in production of automobile frames. A method for producing a steel component having a locally softened part includes the steps of: producing a steel sheet; heating a steel sheet to the temperature of point Ac1 (°C) or above and below point Ac3 (°C)+10°C; processing a steel sheet by subjecting it to a strain of 0.5% or more at a processing temperature of 675°C or above and below point Ac3 (°C)+10° C; holding the deformed steel sheet at the processing temperature for 1-120 seconds or cooling the steel sheet with an average cooling rate from more than 0°C/s up to 15°C/s, for 1-120 seconds. In this case, after the holding or cooling stage, the deformed steel sheet is cooled to the temperature Ms (°C)-50°C, and during the stages of heating, processing and holding the deformed steel sheet, the average cooling rate from the temperature at the heating stage to the temperature Ms (°C)-50°C is controlled as 10°C/s or more, and when carrying out the stages of heating, processing and cooling of the steel sheet with an average cooling rate of more than 0°C/s up to 15°C/s for 1-120 seconds, the average cooling rate from the temperature at the heating stage of the steel sheet to the processing stage and after the cooling stage of the steel sheet with an average cooling rate from more than 0°C/s up to 15°C/s for 1-120 seconds, up to temperature Ms (°C)-50°C is controlled as 10°C/s or more. A steel sheet is obtained having a chemical composition including, in wt.%: C from 0.05 to 0.40, Si from 0 to 2.0, Mn from 1.0 to 3.0, Al from 0.010 to 1.0, P more than 0 and 0.100 or less, S more than 0 and 0.010 or less, N more than 0 and 0.010 or less and B from 0.0005 to 0.010, optionally at least one element from the following groups (a) and (b): (a) one or more elements selected from the group consisting of Cu greater than 0 and 0.50 or less and Ni greater than 0 and 0.50 or less, and (b) one or more element selected from the group consisting of Ti greater than 0 and 0.10 or less, Cr greater than 0 and 3.0 or less and Nb more than 0 and 0.10 or less, with the rest being iron and unavoidable impurities.

EFFECT: obtaining a high-strength steel part having a locally softened part, without regulating the local temperature.

8 cl, 4 dwg, 6 tbl, 4 ex