A method for the manufacture of a coated steel sheet

A steel sheet comprising:

• a steel substrate;
• and
• a coating on the steel substrate, the coating comprising from 10 to 40% of nickel, a balance being zinc,
• the steel substrate having a microstructure comprising from 1 to 50% of residual austenite, from 1 to 60% of martensite and optionally at least one element chosen from:
• bainite, ferrite, cementite and pearlite, and the following chemical composition in weight:
• 0.10<C<0.50%,
• 1.0<Mn<5.0%,
• 0.7<Si<3.0%,
• 0.05<Al<1.0%
• 0.75<(Si+Al)<3.0%
• and on a purely optional basis, one or more elements:
• Nb≤0.5%,
• B≤0.005%,
• Cr≤1.0%,
• Mo≤0.50%,
• Ni≤1.0%,
• Ti≤0.5%,
• a remainder of the composition making up of iron and inevitable impurities resulting from processing.

A method for the manufacture of a coated steel sheet comprising the following steps:

• providing an annealed steel sheet having the following chemical composition in weight:
• 0.10<C<0.50%,
• 1.0<Mn<5.0%,
• 0.7<Si<3.0%,
• 0.05<Al<1.0%
• 0.75<(Si+Al)<3.0%
• and on a purely optional basis, one or more elements:
• Nb≤0.5%,
• B≤0.005%,
• Cr≤1.0%,
• Mo≤0.50%,
• Ni≤1.0%,
• Ti<0.5%, such steel sheet being annealed at a temperature between 600 to 1200° C.;
• and
• coating the annealed steel sheet with a coating comprising from 1 to 40% of nickel, a balance being zinc.