Will salt water rust steel if it is always under water?

http://www.metalwebnews.com/howto/rust/rust.html
"Salt water will cause rust faster than water because salt water is a
better electrical conductor."

Thank you for your question.

skermit-ga

---

Request for Answer Clarification by amiteriver-ga on 05 Oct 2004 17:07 PDT

maybe I should restate the question --  if a piece of steel is under
saltwter will there be a reaction - rust ETC:

---

Clarification of Answer by skermit-ga on 05 Oct 2004 17:28 PDT

Rust will STILL occur on steel, but less fast than if it's sprayed
with, or half submerged under water. Salt water actually speeds this
up. Here's a children's experiment which can help show you how steel
wool will rust in water (you can add salt to see it too).

http://www.chemistry.org/portal/a/c/s/1/wondernetdisplay.html?DOC=wondernet%5Cactivities%5Cmetals%5Crust.html

skermit-ga

Why will it go slower if it stays under water?

Rusting of steel is actually an electrochemical reaction involving
iron and oxygen.  Steel that is completely immersed in water will rust
since even freshwater contains enough solutes to allow for adequate
conductivity.  Saltwater increases the rate even more.  The problem
with being completely submerged is that the concentration of oxygen in
water is only about 7ppm, in air it is around 200000ppm.  So the
problem is a lack of the needed oxygen to actually react with the
iron.