HIGH-STRENGTH COLD-ROLLED STEEL SHEET WITH LOW IN-PLANE ANISOTROPY OF YIELD POINT AND METHOD OF ITS PRODUCTION Russian patent published in 2014 - IPC C22C38/06 C22C38/04 C21D8/04 

FIELD: metallurgy.

SUBSTANCE: high-strength cold-rolled sheet steel with low in-plane anisotropy ΔYP_L making 0.03 or less. Sheet is made of steel containing in wt %: C: 0.06-0.12%, Si: 0.7% or less, Mn: 1.2-2.6%, P: 0.020% or less; S: 0.03% or less; sol. Al: 0.01-0.5%; N: 0.005% or less, at least one of Cr: 0.5 or less, and Mo: 0.5 or less, Fe and unavoidable impurities making the rest. Sheet microstructure consists, in terms of volume fraction relative to the entire microstructure, of 60% or more of ferrite phase as the main phase and 5-20% of martensite phase. Besides, it features the function of distribution of crystal 3D orientation of 2.5 or less in compliance with {φ1, Φ, φ2}={0°, 35°, 45°}.

EFFECT: breaking point of at least 500 MPa and better mouldability.

2 cl, 2 tbl, 1 ex