Abstract
In order to investigate the effects of catholic protection on some alloy surfaces in sea water, tests were conducted with galvanic-coupled and welded specimens with zinc anodes. Gun metal, mild steel and five kinds of stainless steel were immersed in static or flowing (6m/sec) sea water for about one year. The weight loss and the depth of pitting, besides the reduction of tensile strength were measured. Protective effects were calculated from difference of weight losses between protected specimens and unprotected ones, and reduction rates of tensile strength were calculated from difference of tensile strength between corroded specimens and original ones.
Results obtained are as follows:
(1) Protective effects are 88-98% for mild steel in flowing sea water.
(2) Reduction rates of tensile strength are 0-8% except for welded 17-4 PH stainless steel specimen (23%), under the condition of catholic protection in flowing sea water.
