Use of Soft-Metal Engineered Surfaces to Minimize Galling of Carbon Steel Bolting Materials in Gasketed Joints at Elevated Temperatures.

Abstract

Bolting materials with soft-metal engineered surfaces applied using the PlasmaBond process retain their qualifications as pressure boundary materials. These thin, highly adherent gold or silver surfaces significantly reduce the risk of galling for joints that are heavily loaded, operate at elevated temperature, and remain stagnant for long periods. Soft-metal engineered surfaces have demonstrated in joints assembled by tensioning and the more common practice of torquing, offer improved galling resistance compared to non-coated components. Field experience has shown that engineered surfaces can be used to create "metallurgical contrast" that is more effective against galling than conventional lubricants.