| This paper
describes the development concept and quality
properties of a high lubrication galvannealed
steel sheet (GA), “GAN,” in which
the sliding property of GA is greatly improved,
securing the high formability required in
hard-to-form automotive body panels. The developed
product displays press formability equivalent
to that of GA with an Fe-Zn alloy electroplated
layer on the GA surface (double-layered GA),
and spot weldability and adhesive compatibility
superior to those of GA. High lubricity is
obtained in the developed product by applying
an ultra-thin (50nm) Ni-Fe-O inorganic coating.
As the respective roles of these elements,
Fe, Ni, and O improve the anti-sticking property
during press forming, Ni improves affinity
with press oil and spot weldability, and Fe
improves adhesive compatibility. JFE Steel
has also developed an organic lubricant coated
GA with improved lubrication properties and
anti-galling properties. The lubricant coating
can be removed with the press oil in the alkali
degreasing process after press forming. |
