METHOD FOR HEAT TREATMENT OF CASTINGS MADE OF WEAR-RESISTANT CAST STEEL Russian patent published in 2023 - IPC C21D1/78 C22C38/58 C22C38/50 C22C38/44 C22C38/42 

FIELD: metallurgy.

SUBSTANCE: method for heat treatment of castings made of wear-resistant cast steel with high mechanical properties, which can then be used for parts of ore mining and processing and earth-moving equipment operating at high shock loads and subjected to shock-abrasive wear, such as teeth, tooth crowns, interdental protections and walls of excavator buckets, armor of ball mills and crushers, bulldozer blades. The heat treatment method includes normalization followed by tempering and quenching followed by tempering. The casting is made of wear-resistant cast steel containing the following components, wt.%: С: 0.17-0.5, Si: 1.5-2.5, Mn: 1,0-2,0 Cr 0,3-1,0, Ni: 0.2-1.0, Cu: not more than 0.5 (not including 0), Mo: 0.2-0.6, Ti: not more than 0.2 (not including 0), at least one component selected from the following group, if necessary: vanadium not more than 0.02, niobium not more than 0.02, nitrogen not more than 0.02, aluminum not more than 0.1, calcium not more than 0.01, boron not more than 0.01 and tungsten not more than 0.03, the rest is iron and unavoidable impurities. Normalization is carried out at the temperature of 900-1000 °C with exposure for 1.5-4.5 minutes per 1 mm of cross-section, and subsequent tempering is carried out at the temperature of 650-750 °C for 2.5-5.5 minutes per 1 mm of cross-section. The hold time for tempering following normalization is longer than the hold time for normalization. Heating for quenching is carried out to the temperature of 900-1000 °C with exposure for 1.5-3.5 min per 1 mm of cross-section followed by cooling to a temperature below 150 °C and tempering.

EFFECT: high mechanical properties are provided, allowing to operate the products made of steel and subjected to heat treatment under high wear conditions.

8 cl, 3 tbl