PLATE STEEL CHARACTERISED BY LOW RATIO BETWEEN YIELD POINT AND ULTIMATE STRENGTH, HIGH STRENGTH AND HIGH UNIFORM RELATIVE ELONGATION, AND METHOD FOR ITS MANUFACTURE Russian patent published in 2013 - IPC C22C38/14 C21D8/02 

FIELD: metallurgy.

SUBSTANCE: steel contains the following, wt %: C 0.06 to 0.12, Si 0.01 to 1.0, Mn 1.2 to 3.0, P 0.015 and less, S 0.005 and less, Al 0.08 and less, Nb 0.005 to 0.07, Ti 0.005 to 0.025, N 0.010 and less, O 0.005 and less, Fe and inevitable impurities are the rest. Steel microstructure represents a two-phase microstructure consisting of bainite and martensite-austenite component (M-A); fraction of surface area of M-A component is in the range of 3% to 20%, and equivalent diameter of a circle for M-A component is 3.0 mcm and less.

EFFECT: steel is characterised by uniform relative elongation and ratio between yield point and ultimate strength both before and after strain ageing during 30 minutes and less.

3 cl, 3 dwg, 3 tbl, 1 ex