BORON-BEARING STEEL FIT FOR WELDING Russian patent published in 2003 - IPC

FIELD: metallurgy; production of boron- bearing steel. SUBSTANCE: The invention is dealt with metallurgy, in particular with production of the boron-bearing steel with the high fastness: tensile strength - at least of 900 MPa, impact strength, measured with the help of the shock test by Sharpy using V-shaped notch at the temperature of -40 C, at least of 120 joules, and a microstructure containing mainly a close-grained inferior bainite, close-grained lath martensite, or their mixture formed in essence, from nonrecrystallized grains of austenite and containing components in the following ratio (in mass. %): carbon 0.03-0.10, manganese 1.6-2.1, niobium 0.01- 0.1, vanadium 0.01-0.1, molybdenum 0.2-0.5, titanium 0.005-0.03, boron 0.0005-0.002, iron - the rest. At that the carbon equivalent of the steel is in the interval 0,3≤C_e≤0,7, and an index of weldability is P_cm≤0,35. EFFECT: increased strength at the ratio of the yield stress to a limit of tensile strength is less than 0.93. 15 cl, 13 15 cl, 13 dwg, 2 tb