Round Robin Study on Seam Penetration and Rust Protection

Results obtained by a round robin test on seam penetration and protection against corrosion by three different test methods and six varied rust preventative products are presented. The methods were chosen as current practices of industry while the rustproofing materials were typical commercially available items.

This Study was conducted under the auspices of the SAE Automotive Corrosion and Prevention Committee, Division 5 in order to determine the feasibility of using hem flange methods for ranking rustproofing coatings by accelerated laboratory means.

The purpose was to investigate repeatability of the test methods and was performed by four independent laboratories.

Test data indicated said methods had poor correlation between repetitions and sites for evaluating seam penetraton and corrosion protection. Since ranking of coatings changed with hem flange geometry, no one method could be used to differentiate between test coatings. Results established that seam penetration alone cannot be used as a criteria for corrosion protection.