IMPROVEMENT OF THE CORROSION-FATIGUE BEHA VIOR OF STEELS BY PAINT-COATING

Paint-coatings have been used extensively to prevent corrosion of stee l. In order to investigate the influence of an anticorrosive paint on the corrosion fatigue strength of steel, specimens of SAE4135 in a que nched and tempered state, and in salt bath nitrocarburized state, on t he one hand. and specimens of the steel SAE5115 in a salt bath carburi zed state, on the other hand, were subjected to comparative rotating b ending fatigue tests in inert media and in aqueous 5 pct NaCl. The res ults demonstrate that the 5 pct NaCl environment is reducing fatigue l ife drastically, but the painting treatment, however, was found to imp rove significantly the corrosion fatigue life. Regarding the beneficia l effect of the painting treatment on the corrosion fatigue behavior, a superiority of the nitrocarburized variant in contrast to the other variants was ascertained.