Check out our project guide, which talks about how to do a research paper: http://www.sciencebuddies.org/science-f ... ndex.shtml
The guide will walk through through each step of your project. Just look on the left side under "How to Do a Science Fair Project?" and then "Doing Background Research"
For your report, I'd find some websites about steel and how/why rust occurs. Also do some research on what steel is used for in the world, and why do we care if it rusts or not? Does rusting affect how sturdy it is?
Also research what salt is made from (sodium and chlorine NaCl). If you search for "salt steel rust" in Google I'm sure some websites will pop up.
Here are a couple I found:http://science.howstuffworks.com/question445.htm
Here's a page about why stainless steel does not rust: http://www.scientificamerican.com/artic ... nless-stee
You should be able to find many other websites just by putting in a couple of key words like "steel rust" into Google.
I'm going to move your topic to the Physical Science forum so our experts can better help you.
Good luck and let us know if you have more questions.