HOT GALVANISED STEEL SHEET AND METHOD OF ITS PRODUCTION Russian patent published in 2015 - IPC C22C38/04 C23C2/02 C23C2/06 

FIELD: metallurgy.

SUBSTANCE: galvanised steel sheet contains steel sheet and coating on the steel sheet surface. Steel sheet contains in wt %: C 0.05-0.40%, S 0.5-3.0%, Mn 1.5-3.0%, O below 0.006%, P below 0.04%, S below 0.01%, Al below 2.0%, N below 0.01%, rest for Fe and inevitable impurities. The steel sheet microstructure contains from 20% to 99%, on a whole of one or two of martensite and beinite, and rest structures includes ferrite, and one or two of residual austenite below 8 vol %, and pearlite below 10 vol %. Tensile strength of the steel sheet is 980 MPa or more. Coating layer is galvanic layer obtained by immersion in hot bath, or annealed galvanic layer containing oxides comprising one or two, or more components out of Si, Mn and Al, Fe below 15 wt %, and rest for Zn, Al and inevitable impurities. In section comprising steel sheet and galvanic layer reviewed through the sheet thickness the oxides projection area is from 10% to 90%.

EFFECT: resistance against delayed fracture.

10 cl, 4 dwg, 18 tbl