The investigation provides at least a partial answer to the question as to whether improved atmospheric corrosion resistance of alloy steels is advantageous when they are painted. Steels showed a 20:1 difference in corrosion loss between an exceptionally low copper content open hearth iron and typical low alloy high strength steel. A common automobile paint system was used—a pigmented baking alkyd primer with pigmented baking urea modified, alkyd top coats, with and without zinc phosphate (Bonderite) pretreatment. Test panels were exposed 80 and 800 feet from the ocean at Kure Beach, N. C., in an industrial atmosphere at Bayonne, N. J. and in a rural atmosphere at Morenci, Mich. Principal findings were: 1. Low alloy steel performed best; copper steel next. Low copper content open hearth iron worst painted or bare. 2. Zinc phosphate pretreatment improved performance of all painted steels, the advantage increasing with severity of the atmosphere and vulnerability of steels. 3. Best performance was that of low alloy high strength steel, zinc phosphate pretreated. 4. A few weeks’ exposure 80 feet from ocean led to same conclusions as exposure for much longer periods elsewhere. 5. Marine atmosphere 800 feet from ocean was less damaging to bare, but more damaging to painted steel than Bayonne industrial atmosphere.
Effect of Composition of Steel On the Performance of Organic Coatings In Atmospheric Exposure★
F. L. LaQUE—Presently in charge of the Corrosion Engineering Section of the International Nickel Co., Inc., New York City, he has been with Inco since 1927. He has specialized in the properties and applications of corrosion resisting materials. A graduate of Queen’s University, Kingston, Canada, he is a past president of the National Association of Corrosion Engineers, received the NACE Speller Award in 1949, was Edgar Marburg Memorial Lecturer for American Society for Testing Materials in 1951 and currently is active in numerous technical societies interested in corrosion.
JAMES A. BOYLAN—Presently in charge of the Technical Service Section of the Technical Division of The Parker Rust Proof Company, Detroit. He started work for the Parker Company in 1929 in the testing laboratory and has spent most of his time since in the field of corrosion testing and surface treatment.
