HIGH-STRENGTH ELECTROPLATED SHEET STEEL Russian patent published in 2014 - IPC C22C38/04 C22C38/58 C23C2/02 C23C2/06 C23C2/40 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, particularly to electroplated steel sheet with tensile strength of 770 MPa and higher to be used in motor-car construction. This steel consists of sheet steel section, ply of coating made thereon, soft ply adjoining the coating ply interface and inner ply differing from said soft layer. Said steel sheet section contains the following substances, in wt %: C - 0.05-0.50, Si - 0.005-2.5, Mn - 0.01-3.0, P - 0.03 or less, S - 0.02 or less, N: not over 0.0060, one or several from: Al, Ni, Cu, Cr, Mo, B, Ti, Nb, V, rare earth metals and Ca, Fe and unavoidable impurities making the rest. Coating ply is that of electroplated coating or that of annealed electroplated coating. Note here that electroplated coating ply comprises the following substances: Al - 0.01% - 1.5% and one or more elements selected from Pb, Sb, Si, Sn, Mg, Mn, Ni, Cr, Co, Ca, Cu, Li, Ti, Be, Bi rare earth metals making on the whole up to 3,5%, Zn and unavoidable impurities making the rest. Note here that annealed electroplated coating ply comprises the following substances: Fe - 5% - 15%, Al - 0.01% - 1% and one or more elements selected from Pb, Sb, Si, Sn, Mg, Mn, Ni, Cr, Co, Ca, Cu, Li, Ti, Be, Bi and rare earth metals making on the whole up to 3.5%. Note that Zn and unavoidable impurities make the rest.

EFFECT: ruled out cracking, sufficient fatigue strength.

6 cl, 1 dwg, 7 tbl, 4 ex