MANUFACTURING METHOD OF HOT-DIP GALVANISED STRIP (VERSIONS) Russian patent published in 2012 - IPC C21D8/04 C21D9/48 C22C38/42 C23C2/06 

FIELD: metallurgy.

SUBSTANCE: steel containing the following, wt %, is manufactured: C 0.001-0.006, Si not more than 0.15, Mn 0.25-1.60, P not more than 0.12, Cr not more than 0.15, Ni not more than 0.15, Cu not more than 0.15, V not more than 0.010, Mo not more than 0.015, Al 0.01-0.09, N not more than 0.007, S not more than 0.018, iron and inevitable impurities - the rest; according to the first version, steel contains Ti 0.01-0.09 and Nb not more than 0.010 when the ratio Ti≥(4C+3.43N+1.5S) is fulfilled; according to the second version, steel contains Ti 0.01-0.07 and Nb 0.01-0.07 when the ratios Ti≥3.43N, Nb≥7.75C, (Cr+Ni+Cu)≤0.25 are performed; steel pouring, hot rolling which is finished at 830-910°C, water cooling of strip, rolling at 530-730°C, etching, cold rolling, recrystallisation annealing at 750-900°C, application of zinc coating and pinch rolling of strips with crimping of 0.5-2.5%. Steel can also contain the following, wt %: 0.0005-0.005 B and/or 0.0003-0.001 Ca. Carbon equivalent of steel can be determined with the ratio of C_equiv=C+(Mn+Si)/6≤0.28.

EFFECT: improving strength characteristics of the strip and maintaining high ductility, and providing deep forming.

6 cl, 5 tbl