抄録
Lightly tin coated steels with a nickel diffusion layer on steel have been studied on corrosion resistance and weldability. The nickel diffusion layer is provided by nickel-plating and annealing processes through a continuous annealing line.
The nickel diffusion layer plays an important role in improving corrosion resistanec by decreasing the corrosion potential difference between tin and base metal, and by forming a dense and homogeneous Fe (Ni)·Sn2 alloy layer in flow melting process.
A convex and discontinuous structure of the metallic tin layer can be obtained by the flow melting process using a special flux. Metallic tin amount of more than 0.1 g/m2 which is necessary for high speed welding is secured after lacquer baking by the convex and discontinuous structure of the metallic tin layer.
The nickel diffusion layer improves the corrosion resistance after lacquering. Furthermore the chromate layer consists of metallic chromium and hydrated chromium oxide improves the corrosion resistance after lacquering.
