Preventing and Solving Delamination During Multilayer Pipeline Girth Weld Coating Application

Multilayer Coatings: Enri-of-Pipe Adhesion Issues For FBE coatings, délamination in the cutback area of the girth weld is a rare occurrence, however, for multilayer systems, it is not uncommon (Fig. 1, p. 44), Chang, et al, evaluated the causes of disbandment far three-layer pipe coating systems.12 One of the underlying causes is residual stress In the coating as a result of the application process. To minimize the possibility of coating délamination in the cutback area: * utilize world-class coating materials and application processes: * minimize the time ihe cutback interface is exposed to the atmosphere without protection; * in case of prolonged storage time, implement suitable protective measures such as wraps, peelable coatings, or vapor phase inhibitors; * include an FBE tail to minimize the influence of stresses; and * keep the chamfer angle down to 30 degrees.