To provide a steel sheet excellent in painting bake hardenability and anti
aging property at room temperature: containing, in mass, 0.0001 to 0.20%
of C, 2.0% or less of Si, 3.0% or less of Mn, 0.15% or less of P, 0.015%
or less of S, and, in addition, 010% or less of Al and 0.001 to 0.10% of N
so as to satisfy the expression 0.52Al/N<5 and, further, one or more of
2.5% or less of Cr, 1.0% or less of Mo and 0.1% or less of V so as to
satisfy the expression (Cr+3.5MO+39V) .gtoreq.0.1, with the balance
consisting of Fe and unavoidable impurities; having the value of BH170,
evaluated after applying a 2% tensile deformation and then a heat
treatment at 170.degree. C. for 20 min., being 45 MPa or more, and any of
the value of BH160, evaluated after applying a 2% tensile deformation and
then a heat treatment at 160.degree. C. for 10 min., and the value of
BH150, evaluated after applying a 2% tensile deformation and then a heat
treatment at 150.degree. C. for 10 min., being 35 MPa or more; and having
the yield point elongation at a tensile test after applying a heat
treatment at 100.degree. C. for 1 h. being 0.6% or less.
Um ein Stahlblech zur Verfügung zu stellen, das im Anstrich ausgezeichnet ist backen Sie Hardenability und Anti- alternde Eigenschaft bei der Raumtemperatur: , in der Masse, 0.0001 bis 0.20% enthalten von C, 2.0% oder kleiner von Silikon, 3.0% oder kleiner von Mangan, 0.15% oder kleiner von P, 0.015% oder kleiner von S und, zusätzlich, 010% oder kleiner von Al und 0.001 bis 0.10% von N damit den Ausdruck 0.52Al/N erfüllen
