THE EFFECT OF PERLITE AND MINERAL WOOL LEACHATE SOLUTIONS ON THE CORROSION BEHAVIOURS OF PIPELINE STEELS

Abstract

This study provides an extensive in-depth analysis of the issue of corrosion under insulation (CUI), with an overview of the capabilities and limitations of the latest nondestructive evaluation techniques, commonly employed for inspection of CUI systems. CUI is difficult to identify because it remains hidden beneath the insulation hardware, often resulting in unexpected failures, and can occur under any class of insulating material. The main problem to address is the ingress of water into the insulation, through damaged sealants and compounds to form leachate solutions. Given the paramount significance of insulation choice in influencing Corrosion Under Insulation (CUI), the study focused on investigating two distinct insulation types: perlite and mineral wool insulation. Leachate solutions were meticulously extracted from these insulations, forming the basis for subsequent comprehensive testing procedures. These solutions were used in the experimental phase where (12) AISI 1018 steel coupons and (12) X52 coupons were examined. A diverse array of tests was employed to discern the composition of the solutions, delve into the surface properties of the tested coupons, and quantify corrosion rates. Through this systematic approach, our objective was to uncover the profound impact of insulation on corrosion dynamics and to elucidate how the selection of insulation for a given pipeline system can significantly influence the system's lifespan, either by mitigating or expediting the corrosion process.