Electrogalvanized or Hot Dip Galvanized — Results of Five Years Undervehicle Corrosion Testing

The corrosion performance of 17 hot dip and electrolytic zinc and zinc alloy coated steel samples exposed for five consecutive winters in undervehicle tests is reported in this paper. The program initiated by Dofasco in 1981, used two commercial trucks operating in the deicing salt/snow belt region of Southern Ontario, Canada.

Results of the phosphated and cathodic primed coupons confirmed our previous observations on unpainted coupons that the hot dip coated steels with the thicker coatings outperformed the electrolytic coated steels.

A new test program Has started in 1984. This program uses paired “t” test statistics to compare the undervehicle corrosion performance of hot dip and electrogalvanized coupons of similar coating mass. Results after one and two winters will be presented.