Stress Corrosion Cracking Resistance of High Strength 18%Cr Cast Stainless Steel in Sea Water

Recently, new high strength 18%Cr cast stainless steel has been put into practical use for marine propellers. The stress corrosion cracking resistance of this steel in sea water was compared with that of other cast stainless steels such as martensitic cast stainless steel.The results are summarized as follows:(1) No crack is found regardless of the heat treatment condition of high strength 18%Cr cast stainless steel (C≤0.04), after the stress corrosion cracking test was carried out under cathodic protection with zinc.(2) The stress corrosion cracking resistance of this steel in sea water is as superior as that of two-phase cast stainless steel.(3) In order to maintain the superior stress corrosion cracking resistance of this steel, the upper limit of carbon content should be controlled as low as possible and strong cold working should be avoided.