REINFORCED STRUCTURAL STEEL WITH ENHANCED STRENGTH AND METHOD OF THERMAL STRENGTHENING HOT ROLLED STOCK Russian patent published in 2015 - IPC C22C38/32 C22C38/54 C21D8/10 

FIELD: metallurgy.

SUBSTANCE: steel which contains the following, wt %, is made: carbon 0.40-0.45, silicon 0.15-0.30, manganese 0.75-1.00, sulphur 0.025 or less, phosphor 0.025 or less, copper 0.30 or less, nickel 0.30 or less, chrome 0.80-1,10 or less, molybdenum 0.15-0.25, aluminium 0.015 - 0.05, boron 0.00010-0.00025, nitrogen 0.008 or less, the rest is iron and admixtures. Steel is cast, hot-rolled, normalised, cooled in air, and tempered. Normalisation is performed at 880°C, and tempering is performed at 580-600°C.

EFFECT: provision of required operational properties, yield strength of 720 MPa or more and tensile strength 930-1000 MPA with preservation of required plasticity level.

2 cl, 2 tbl