Hi John
I'm not sure what the "
best" would be, but some
very good ones are CPM 154(

), 154CM, ATS34, CPM S30V, CPM S90V and the good old standby 440
C.
All of the above mentioned stainless blade steels, (along with some that aren't mentioned), have very good corrosion resistance. I have
zero first hand experience when it comes to
actual salt water testing, so take this answer to your question "with a grain of ..... errr ....." lets just say...... ymmv
