GALVANISED STEEL OR GALVANISED AND ANNEALED SILICON STEEL Russian patent published in 2012 - IPC C21D9/48 C23C2/06 C22C38/02 

FIELD: metallurgy.

SUBSTANCE: steel plate with coating on the basis of zinc or on the basis of zinc-iron alloy contains the following components, wt %: 0,01≤C≤0.22, 0.50≤Mn≤2.0, 0.2≤Si≤3.0, 0.005≤Al≤2.0, Mo≤1.0, Cr≤1.0, P≤0.02, Ti≤0.20, V≤0.40, Ni≤1.0, Nb≤0.20, iron and inevitable impurities are the rest; at that, steel plate includes layer of internal nitride from at least nitride of one type, which has been chosen from the group consisting of Si nitride, Mn nitride, Al nitride, complex nitride containing Si and Mn and/or Al and Si, and/or Al and Mn, or complex nitride containing Si, Mn and Al, and it does not include any additional external layer of iron nitride. Plate manufacturing method involves plate annealing in the furnace consisting of the following: the first heating zone to temperature T1 in atmosphere with dew point below -30°C; the second zone from temperature T1 to T2 in atmosphere with dew point of -30 to -10°C; the third zone from temperature T2 to T3 in atmosphere with dew point below -30°C; exposure zone at T3 during time t3 in atmosphere with dew point below -30°C; cooling zone of plate in atmosphere with dew point below -30°C, after annealing there performed is zinc plating of steel plate by hot dipping method and, if necessary, plate heat treatment with coating on the basis of zinc is performed.

EFFECT: providing high mechanical properties, sufficient wetting property of surface and adhesion.

18 cl, 3 ex, 2 tbl, 3 dwg