Figure 9. Typical Thickness Loss for Brass Alloys in Marine Atmospheres as a Function of Time (ASM, 2005b)
The corrosion rate of ductile iron is relatively low in industrial environments (such as those found near manufacturing plants and power plants), and is generally less than 5 mils per year. The atmospheric corrosion rates for ductile iron are primarily determined by the relative humidity and the presence of contaminant gases. Sulfur dioxide and other sulfur-bearing compounds as well as high chlorides near marine environments will increase the attack ductile iron.
The atmospheric corrosion Type 302 stainless steel in a typical industrial environment is very low, and samples that have been exposed for two decades in these environments were free from rust stains. However, rust stains were found on coupons after only eight months on samples exposed to a severe industrial environment (such as foundries, refineries, and chemical process plants) that was producing chlorine or hydrogen chloride.
The atmospheric corrosion resistance of piano wire is poor and in most locations will rapidly corrode unless protected, coated, or otherwise sheltered from the high relative humidity or other atmospheric contaminants. Because the thickness of the spring wire is small, very little reduction in diameter would be needed to result in a failure.
Alternative Underground Propane Tank Materials, Phase II—Final Report
September 2009 Battelle and Lincoln Composites