Test (ASTM B117)
"Structural Steel plate bearing heavy coatings of hot dipped galvanized films and Z.R.C. cold galvanizing films have been simultaneously exposed in 5% salt spray for 4538 hours. Deterioration of the hot dipped galvanized films was found to be much more rapid than was the deterioration of the Z.R.C. films, resulting in the development of much more copious quantities of zinc corrosion product, and comparatively more (if limited) ferric corrosion breakthrough on the general panel areas. The quality of performance from the heavier, hot dipped galvanized film is significantly improved compared to that produced by thin galvanized films on galvanized panels normally used as test coupons by the paint industry. The performance of Z.R.C., however, remains superior." Clive H. Hare, Inc. December 27, 1995.
Table I: Panel Ratings after 4538 Hours 5% Salt Spray Exposure
*Rated on a Semi Quantitative Scale of 0-10 (Complete Corrosion-No Corrosion).
**Rated as per ASTM D-610. Edge Corrosion Ignored.
***Rated as 0-10 (Decreasing Blistering Degree)/0-10 (Decreasing Blister Size).