Numerous industrial facilities, especially offshore oil and gas installations, are plagued by bolt corrosion
problems. With a limited record of success in prevention or cure, material loss from corrosion is often
factored into maintenance planning, with bolt replacement as a solution when integrity is threatened.
An increasing focus on overall maintenance as an essential part of reducing problems in safety-critical
systems makes the prevention of corrosion effects on basic components such as bolts and fasteners an
increasingly important goal. This paper describes a corrosion-inhibiting sprayable thermoplastic system
that has demonstrated success in the provision of extended corrosion protection on both new and
rusting bolts in extreme conditions.
The system uses purpose-built equipment to spray a thermoplastic material containing inhibiting oils to
encapsulate the substrate. The paper includes a review of current bolt coating systems and describes
the thermoplastic system, together with field case histories showing how this product has effectively
prevented or stopped on-going bolt corrosion issues found in offshore oil and gas production systems
as well as the in mining industry and on LPG tankers.
Keywords: alloy, bolt, corrosion, encapsulation, fastener, flange, gas, inhibiting, offshore, oil, plating,
sprayable, thermoplastic, valve, zinc