METHOD FOR WATER-AND-AIR QUENCHING OF LARGE-SIZED MOLDS WITH A GIVEN DISTRIBUTION OF STRUCTURES ALONG THE CROSS-SECTION FROM THE WORKING SURFACE TO THE SHANK Russian patent published in 2022 - IPC C21D1/06 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, in particular to methods and devices for heat treatment of large-sized molds. The method for controlled water-air quenching of large-sized molds with a given distribution of structures along the cross-section from the working surface to the shank includes heating the mold to the quenching temperature and controlled cooling of the mold with a water-and-air mixture. The controlled cooling of the working surface is carried out with sprayed water, and the side faces and the shank with an air stream or calm air, while the cooling of the working surface is carried out with sprayed water with a specific flow rate of 0.5-0.65 l/m²c to ensure the beginning of martensitic transformation in a layer 30 mm deep 300 s after the start of quenching, then cooling is carried out with a lower cooling intensity sprayed with water with a specific flow rate of 0.27-0.4 l/m²c with the provision of the beginning of bainite transformation in a layer with a depth of 60 mm 540 s after the start of quenching, and then cooling is carried out in calm air until the temperature equalizes along the cross section of the mold. It is possible to obtain the necessary distribution of microstructures with certain mechanical properties along the cross section of the mold from the working surface to the shank at a safe level of quenching stresses.

EFFECT: operational durability of molds increases due to an increase in the hardness of the working layer and its depth.

1 cl, 3 dwg, 1 tbl