Steel is stronger than iron in most cases. Although most types of iron are harder than steel due to a higher carbon content, they are also more brittle and therefore weaker.
Steel is a type of iron where the carbon content has been reduced and most of the impurities have been removed from the metal. Pig iron contains approximately 4 to 5% carbon, and most types of steel contain .5 to 2%. The lower carbon content of steel makes it more malleable and less subject to corrosion and rust. Other metals are also commonly added to steel to create alloys, such as chromium in stainless steel, to reduce corrosion and add strength. Steel alloys are much stronger than other types of iron.