THREE-PHASE NANOCOMPOSITE STEELS Russian patent published in 2007 - IPC C21D8/00 C22C38/40 C22C38/58 

FIELD: metallurgy industry; production of the three-phase nanocomposite high-performance carbon steels.

SUBSTANCE: the invention is pertaining to the field of metallurgy industry, in particular, to production of the high-performance carbon steels. The invention presents the carbon steel and the method of its production. The carbon steel contains iron and no more than 0.35 mass % of carbon, the three-phase microstructure containing the ferrite crystals is interfused with the martensite-austenitic grains, at that the martensite-austenitic grains contain the martensite laminas alternating with the thin austenitic films. The method includes: formation of the steel composition containing iron, at least one alloying component and no more than 0.35 mass % of carbon in the ratios chosen for production of the composition with the temperature of the beginning of the martensite transformation at least at about 300 °С; heating of the indicated steel to the temperature sufficient for its transform into the uniform austenitic phase and transfer of all the alloying components into the soluble state; refrigeration of the uniform austenitic phase in the sufficient degree for transformation of a part of the austenitic phase into the ferrite crystals for formation of the two-phase microstructure containing the ferrite crystals fusion-spliced with the austenitic grains; refrigeration of the two-phase microstructure in the field of the phase transformation of the martensite for transformation of the austenitic grains into the lattice three-phase microstructure containing the laminas of martensite alternating with the films of the residual austenitic. The technical result of the invention is production of the high-strength corrosion- resistant carbon steel with the crystalline structure ensuring the exclusive properties as compared with the common steels.

EFFECT: the invention ensures production of the high-strength corrosion- resistant carbon steel with the crystalline structure having the exclusive properties as compared with the common steels.

10 cl, 5 dwg