HIGH STRENGTH HOT GALVANISED STEEL PLATE AND METHOD OF ITS PRODUCTION Russian patent published in 2016 - IPC C22C38/06 C21D8/02 C23C2/02 C23C2/06 C23C2/28 

FIELD: metallurgy.

SUBSTANCE: plate is made from steel containing in wt %: C: from 0.10 to 0.4, Si: from 0.01 to 0.5, Mn: from 1.0 to 3.0, O: 0.006 or less, P: 0.04 or less; S: 0.01 or less, Al: from 0.1 to 3.0, N: 0.01 or less, and rest for Fe and inevitable admixtures, at that Si+Al≥0.5. Plate surface has hot galvanised alloy containing Fe in amount of below 7 wt %, rest - Zn, Al and inevitable admixtures. Plate steel structure contains in 40 vol % or over of ferrite as main phase, from 8 to 60 vol % residual austenite, rest up to 100 vol % at least one out of beinite, martensite and pearlite. Number of grains of residual austenite with average residual stress σR complying with -400 MPa≤σR≤200 MPa, is 50% or over of quantity of the residual austenite.

EFFECT: high elongation and V-shape bending upon keeping the required strength.

6 cl, 6 dwg, 2 tbl, 1 ex