STEELMAKING EQUIPMENT
THERMAL SPRAYED TO PROTECT AGAINST CORROSION
SUMMARY

Coatings of System #54, a plasma overlay of elemental aluminum followed by a high temperature sealer, are applied to steelmaking equipment in order to prevent loss from corrosion. Components exposed to high temperatures, humid conditions, salt or fresh water spray can be protected with this low cost overlay. Carbon steel weldments and foundry iron castings are most often treated. The purpose of this coating is long term protection and lower maintenance costs.

BACKGROUND

Foundry and steelmaking equipment is often made from carbon steel or low grade cast iron in order to reduce costs. Sales of replacement parts are guaranteed. Water cooled rollers and edge guides are exposed to conditions varying from humid conditions to high pressure water blasts. Stainless steel systems have to be custom made and are very expensive. High temperature paints have limited strength and poor bonding. Chrome Plating is expensive and environmentally unfriendly.

TECHNICAL

Corrosion is the deterioration of a substance because of a reaction with its environment. Corrosion of carbon steel is caused by the migration of ions from the iron at elevated temperatures and the formation of iron oxide (rust) at lower and humid conditions. All of the processes mentioned above do nothing to prevent this except to exclude the environment. If the paint gets a scratch, then the part rusts.

COATING

System #54 is the only process that bonds elemental aluminum directly to the substrate using a Plasma Coating System that was developed by NASA to test re-entry heat shields on spacecraft. This is metallurgical protection. The electromotive process is reversed. The corrosion is stopped. Scratch through the aluminum and it still will not rust. The coating is stable at temperatures up to 1200 deg. F. and will not migrate or dissolve. It is used extensively for the protection of steelmaking equipment, oil refining equipment, chemical processing equipment, and marine vessels.

CERTIFICATIONS

Pratt and Whitney Aircraft PWA 132

Detroit Diesel Allison 207-2-402

U.S. Air Force AF04 (694) 916

General Electric Company B50TF57-S4

Rolls Royce Specification 9507/13