What is the difference between steel and stainless steel?
Steel is an alloy of iron and carbon. Steel is not rust-free, when it is exposed to air it undergoes oxidation to form rust.
Whereas stainless steel is an alloy of iron in which a very small amount of carbon and nickel and chromium is added by mass. Stainless steel as the name suggests is stain-free or rust-free. It doesn't undergo any oxidation when exposed to air.