Hot Dip Aluminized Steel Sheet - An Excellent Material for Fuel Tank Application

In 1989 Daimler Benz AG, Stuttgart, introduced hot dip aluminized steel sheet for this application in passenger vehicles. By now, after 10 years' experience, most of this manufacturer's current models are equipped with fuel tanks made from aluminized steel sheet.

This material incorporates a combination of a specially designed deep drawing IF steel with the excellent corrosion protection properties of Al coatings. The two methods for joining the upper and lower halves of the tank body are resistance roller seam welding with an additional wire or laser beam welding. The first method was applied to the fuel tank bodies illustrated in this paper.

In laboratory corrosion test series, aluminized steel sheet performed very well with regard to fuel resistance, including resistance to fuels containing methanol and rape-methyl-ester (bio diesel). Attempts to improve external corrosion resistance by in-line chromate treatment were successful. An additional thin organic film (1-2 μm) will be applied for extremely high corrosion requirements, so that 2000 hours without red rust in the salt spray test is a realistic expectation.