Galvanic Corrosion of Selected Tubesheet/Tube Couples under Simulated Seawater Condenser Conditions

Abstract A study was undertaken to investigate galvanic corrosion between copper alloy tubesheets and selected tubing materials under simulated seawater condenser conditions. The study focused primarily on two tubing alloys — Allegheny Ludlum's 6X stainless steel alloy and TIMET's Ti-50A, a commercially pure titanium alloy. The results of 7 months simulated laboratory testing suggest: (1) the use of either titanium or AL-6X tubes with a,copper alloy tubesheet can result in significant galvanic corrosion of the tubesheet; (2) titanium tubes will tend to galvanically corrode a copper alloy tubesheet at a higher rate than stainless steel tubes in seawater; (3) as a tubesheet material, aluminum bronze is significantly less susceptible to galvanic corrosion than the Muntz alloy; (4) a Muntz alloy tubesheet can be expected to dezincify at rates exceeding 2.5 mm/y, when coupled to either titanium or AL 6X tubes; (5) galvanic corrosion will tend to be worse on inlet end tubesheets than on outlet end tubesheets; (6) galvanic corrosion of copper alloy tubesheets will double with every 10°C rise in cooling water (seawater) temperature.