From Corrosion to Confidence

The client’s fleet was equipped with PSS Shaft Seals utilizing a 316L stainless steel rotor. After just 2 - 3 years of service, the mating face of the rotor would begin to corrode, leading to seal leakage. This recurring issue resulted in increased maintenance costs and vessel downtime, as the rotor required frequent replacement to maintain seal integrity.

The corrosion observed was primarily due to electrolysis caused by stray electrical currents present in the marine environment. While 316L stainless steel offers good general corrosion resistance, it is susceptible to accelerated degradation when exposed to stray currents. These conditions create an electrochemical reaction that breaks down the protective oxide layer on the stainless steel, especially at the mating face where the seal interfaces with the carbon stator. As a result, the rotor would corrode prematurely, compromising the effectiveness of the shaft seal and necessitating frequent replacements. To address this, it was necessary to select a rotor material with superior resistance, ensuring longer service life and improved reliability for the vessels.