FIELD: metallurgy.
SUBSTANCE: invention relates to metallurgy. Disclosed is a high-strength hot-rolled steel strip with high resistance to edge cracking. It is made of steel with an elastic limit of Rp0.2 from 660 to 820 MPa, a BH2 value of more than 30 MPa and a hole expansion ratio of more than 30%. It has the following chemical composition, wt%: C - 0,04-0,12, Si - 0,03-0,8, Mn - 1-2,5, P max - 0,08, S max - 0,01, N max - 0,01, Al - no more than 0,1, Ni + Mo - no more than 0,5, Nb - no more than 0,08, Ti - no more than 0,2, Nb + Ti min - 0,03, Cr - no more than 0,6, the rest is represented by iron and inevitable accompanying elements. The microstructure consists of two main components, the first main component has a structure fraction of at least 50% and contains at least one phase component: ferrite, tempered bainite and tempered martensite with a carbide content of less than 5% each. The second main component has the proportion of the structure of 5-50% and contains at least one phase component: martensite, retained austenite, bainite and pearlite. The second main microstructure component has a higher carbon content than the first main microstructure component, and is embedded in the form of inclusions in the less carbon-rich first matrix-forming main microstructure componen. These inclusions are uniformly distributed throughout the strip thickness and have a size of less than 2 mcm. The strip is characterized by high resistance to the formation of edge cracks and a high rate of heat hardening.
EFFECT: invention ensures high resistance to edge cracking.
9 cl, 2 tbl
