Steel

A steel comprising:

• a steel sheet substrate;
• and
• a protective film formed on at least a part of a surface of the steel sheet substrate,
• wherein a chemical composition of the steel sheet substrate is, by mass %,
• C:
• 0.25% to 0.65%;
• Si:
• 0.05% to 2.00%;
• Mn:
• 0.30% to 3.00%;
• P:
• 0.050% or less;
• S:
• 0.0100% or less;
• N:
• 0.010% or less;
• O:
• 0.010% or less;
• Cr:
• 0.05% to 1.00%;
• Cu:
• 0.10% to 1.00%;
• Ti:
• 0% to 0.10%;
• B:
• 0% to 0.0100%;
• Mo:
• 0% to 1.00%;
• Ni:
• 0% to 1.00%;
• Nb:
• 0% to 0.10%;
• V:
• 0% to 1.00%;
• Ca:
• 0% to 0.010%;
• Mg:
• 0% to 0.010%;
• Al:
• 0% to 1.00%;
• Sn:
• 0% to 1.00%;
• W:
• 0% to 1.00%;
• Sb:
• 0% to 1.00%;
• Zr:
• 0% to 1.00%;
• Co:
• 0% to 1.00%;
• REM:
• 0% to 0.30%;
• and
• a remainder:
• Fe and an impurity,
• in an X-ray analysis in which measurement is carried out using a CuKα radiation, in a case where a peak intensity at a diffraction angle (2θ) position of 36.6±0.5° is regarded as 100%, the protective film has a peak having a peak intensity of more than 250% at a diffraction angle (2θ) position of 35.5±0.5° and
• a tensile strength is more than 1,500 MPa.