Materials Performance

AUG 2016

Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.

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44 AUGUST 2016 MATERIALS PERFORMANCE NACE INTERNATIONAL: VOL. 55, NO.8 COATINGS & LININGS F Pipes are common pieces of equip- ment throughout many industries, and wherever there are pipes there are likely to be flanges. An innova- tive solution has been developed for corrosion protection of flanged cou- plings. The operating environment to which flanged pipework is sub- jected can lead to external corro- sion, metal loss, and seizing of flange bolts, among other problems. These can result in plant shutdowns, waste of valuable resources, efficiency re- duction, and costly maintenance ex- penses. By using a flexible, liquid- applied elastomeric material that can be peeled off for inspection and then resealed, flanged pipework can be isolated from corrosive en - vironments. This practical solution enables material selection engi- neers to make informed decisions regarding corrosion protection strat- egies for flanged pipework. Flanges are pieces of equipment used for F eces Flanges are pieces of equipment used for F of equipment used for joining together pipe sections and fittings, F ining joining together pipe sections and fittings, F together pipe sections and fittings, such as valves. The fluid in the pipe could F uch such as valves. The fluid in the pipe could F as valves. The fluid in the pipe could be a liquid, gas, or slurry depending on the F e be a liquid, gas, or slurry depending on the F a be a liquid, gas, or slurry depending on the F liquid be a liquid, gas, or slurry depending on the F gas, be a liquid, gas, or slurry depending on the F or slurry depending on the industry. Carbon steels (CS) are among the F y industry. Carbon steels (CS) are among the F on industry. Carbon steels (CS) are among the F steels (CS) are among the most common materials of construction F ost most common materials of construction F common materials of construction and account for ~80% of all vessels used in F nd and account for ~80% of all vessels used in F account for ~80% of all vessels used in the industry. F e industry. 1 Flanges are no exceptions, and and CS flanges will corrode like other con- F CS flanges will corrode like other con- ventional materials if they are exposed to electroly t es. Isolating th e f lange from aggressive electrolytes is critical for it to function effectively. Flanges are particularly susceptible to corrosion because of their fundamental de- sign. The void between the flange faces can readily trap moisture, which leads to crev- ice corrosion. The use of dissimilar metals for the bolts and other fasteners can lead to galvanic corrosion. Weld areas typically are rough and can trap moisture. Additionally, the external surfaces of the flange and con- nected pipe are often made of CS, and are therefore subject to corrosion. Flange cor- rosion can be exacerbated by factors such as elevated service temperatures, high hu- midity, salty marine environments, or pol- lutant gases. This creates a need for some form of corrosion protection. Thi s article presents an innovative polymeric solution for the protection of the external surfaces of flanges. While this ap- plication focuses primarily on C S, th e threats and solutions for other metallic sys- tems are quite similar. Designing a New Flange Protection Solution For any external corrosion protection system for f langes to be technically and commercially successful, it needs to fulfill four key requirements: • Excellent corrosion protection—this is the primary purpose for the design. • Ease of application/installation—if the solution is difficult to use, then the maintenance personnel respon- sible will be unlikely to use it. Innovative Polymeric Solution for Flanged Pipework Protection o SM ay o harri Z , Belzona, Inc., Miami, Florida

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