3. Surface treatments

3.1 General

Hot-dip galvanizing of finished parts, the traditional form of corrosion protection, has evolved considerably over the last 20 years in its application to sheet steel. In the automotive industry, for example, single-sided electro-galvanized sheet metal began to appear in 1975. As the automotive market increasingly focused on products that prevented corrosion on vehicle exteriors, double-sided coatings began to develop in the 1980s, mainly in Japan. In 1989, Japan rediscovered hot-dip coatings with alloyed galvanized products, and they were emulated the world over.

In today's cars, the percentage of coated sheet...