NODULAR CAST IRON, EUTECTIC CEMENTITE INCLUSIONS AND BAINITE-AUSTENITIC METAL BASE HEAT TREATMENT METHOD Russian patent published in 2019 - IPC C21D5/14 C22C37/04 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, in particular to methods of heat treatment of nodular cast irons, and can be used to obtain wear-resistant products. Method of heat treatment of cast iron containing silicon and manganese as alloying elements, with obtaining a structure with spherical graphite, inclusions of eutectic cementite and a bainite-austenitic metal base, includes heat treatment in two stages, while in the first stage the blank is heated to a temperature of 940–960 °C, kept for 1.0–1.5 h and subjected to quenching by cooling in water to 450–500 °C and then on the air, in the second stage, the blanks are heated in a salt bath to a temperature of 1,150–1,160 °C, kept there for 1.0–1.5 minutes, transfer them to the salt bath with a temperature of 360–380 °C, kept for 1.0–1.5 h, followed by cooling in water and tempering at a temperature of 200–220 °C for 1.5–2 hours.

EFFECT: production of cast iron with a high level of strength, toughness and wear resistance due to the creation in it of a matrix structure of a dispersion-strengthened macrostructured composite, which consists of spherical particles of graphite uniformly arranged in a bainite-austenitic matrix, enclosed in a solid sheath of ledeburite.

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