Hot-dip galvanized hot-rolled and cold-rolled steel sheets excellent in strain age hardening property

A hot-dip galvanized steel sheet excellent in press-formability and strain age hardening property as represented by a ΔTS of 80 MPa or more, comprising:

• a hot-rolled steel sheet having a chemical composition comprising, in weight percentage:
• C:
• 0.15% or less, Si:
• 2.0% or less, Mn:
• 3.0% or less, P:
• 0.1% or less, S:
• 0.02%, or less, Al:
• 0.1% or less, N:
• 0.02% or less,
• 0.05 to 2.0% W, and the balance Fe and incidental impurities and having a structure with a ferrite phase as a main phase forming a composite structure with a secondary phase containing a martensite phase in an area ratio of 2% or more and a fine carbide of W is strain-induced-precipitated in martensite in the secondary phase after a heat treatment at a temperature within a range of 150-350° C., which follows a pre-deformation of 5% or more;
• and
• a hot-dip galvanizing layer or an alloyed hot-dip galvanizing layer formed on a surface of the steel sheet.