HIGH-STRENGTH STEEL SHEET WITH MOLTEN ZINC COAT AND METHOD OF MANUFACTURE OF SUCH SHEET Russian patent published in 2007 - IPC C22C38/04 C22C38/58 C23C2/06 C21D1/26 

FIELD: manufacture of steel sheets by continuous zinc-plating.

SUBSTANCE: proposed zinc-coated steel sheet has galvanic coat layer made from Zn containing aluminum at concentration of from 0.01 to 1 weight-%, the remainder being Zn and unavoidable admixtures; it contains oxide particles within 2 mcm from interface of steel sheet whose average diameter ranges from 0.001 to 1 mcm; oxides are of one type selected from Al oxide, Si oxide, Mn oxide or complex oxide containing at least two elements from Al, Si and Mn. Heating temperature at re-crystallization annealing stage in reduction furnace ranges from 650^°C to 900^°C; steel sheet is passed through atmosphere where ratio of partial pressure of water steam P_H2O and partial pressure of hydrogen P_H2 satisfies the following inequality: forming the oxide in area reaching the depth of 2 mcm from surface of steel sheet; then, sheet is subjected to zinc-plating.

EFFECT: enhanced strength and deformability; possesses good ability for adhesion with galvanic layer; avoidance of defects in galvanic coat.

4 cl, 1 dwg, 3 tbl