MULTI-PHASE STEEL COLD-ROLLED FLAT PRODUCT WHICH IS PRODUCED FROM A MULTI-PHASE STEEL OF THIS TYPE AND METHOD FOR PRODUCING IT

摘要

The present invention provides a cold rolled flat product made of composite textured steel having a composite textural steel and an optimized combination of properties of high strength and good processability. The composite structure steel according to the present invention comprises 0.14 to 0.25% of C, 1.7 to 2.5% of Mn, 0.2 to 0.7% of Si, 0.5 to 1.5% of Al, Cr: 0.1%, Mo: 0.05%, N: 0.02-0.06%, S: 0.01%, P: 0.02%, N: 0.01% and optionally Ti: 0.1%, B: 0.002% and V: 0.15% Containing at least one element in the " Ti, B, V " group according to the present invention, with the balance iron and unavoidable impurities, wherein at least 10% by volume of ferrite and at least 6% by volume of retained austenite are present in the microstructure of the steel , Tensile strength of steel (R_m) Is at least 950 MPa and the yield point (R_eL) Is at least 500 MPa and the measured elongation at break (A₈₀) Is at least 15%. The present invention also provides a method for producing a flat product according to the present invention.