Failure analysis of a titanium plate heat exchanger – Mechanical fatigue

Abstract This article presents a failure analysis of a plate heat exchanger. The equipment aims to decrease fresh water temperature using seawater as the cooling medium. The plates were manufactured from ASTM B265 Grade 1 titanium. After 126.000 h of operation, low thermal efficiency became evident and the equipment was shutdown for inspection. Visual inspection detected plates with through-wall cracks. To identify the mechanisms and causes of failure, the investigation included: visual inspection, chemical analysis via optical emission spectroscopy (OES), metallography, fractography, 3D laser scanning and finite element stress analysis. The plates failed due to mechanical fatigue caused by service loading fluctuations.