Thermal and Corrosion Behavior of Polyurethane Coating on Stainless Steel Pipelines Under the Sea

This paper investigates the thermal and erosion behavior of polyurethane coatings applied to subsea stainless-steel pipelines, with special focus on elbow sections which are most vulnerable to degradation due to flow impingement, thermal cycling, and corrosive seawater environment. Experimental work includes the application of polyurethane coating on test pipeline steel specimens, exposure to cyclic temperature variations mimicking subsea conditions, and slurry erosion tests simulating particle-laden flow. Comparative performance is evaluated against conventional coatings (Ni-P, HVOF WC-10Co4Cr). The results indicate that polyurethane coatings maintain good adhesion and structural integrity under thermal cycling, significantly reduce erosion rates in elbow regions, and offer cost-effective protection compared to more complex coating systems. Implications for design, maintenance, and life-prediction of offshore pipelines are discussed. Keywords include polyurethane coatings; thermal stress; erosion resistance; subsea pipelines; surface engineering; corrosion protection.