A steel composition, in which, Si content is regulated to a given range and
Nb and Cu or Ni, Mo are compositively added, and a recrystallization
annealing is carried out to form an internal oxide layer just beneath a
surface of a steel sheet and a surface oxide simultaneously formed on the
surface of the steel sheet is removed by pickling. As a result, the
formation of oxides of Si, Mn and the like is considerably decreased on
the surface of the steel sheet in a subsequent heating before plating
because the above internal oxide layer acts as a diffusion barrier. Thus,
there can be obtained high tensile strength hot-dipped steel sheets having
a considerably excellent plating property.
