We use steel for many things, from beams in buildings to the hulls of ships. Steel is useful for its high strength and several other properties. But why is steel so much stronger than other metals? Why are there so many types of steel, and do they vary in strength? Here are some answers to your steel-related questions.
What is Steel?
Steel is an alloy, or a combination of different metals, or of a metal with a nonmetal. We make steel by combining iron with carbon (which is a nonmetal), and sometimes other materials too. Usually, we create alloys because they have better properties than the individual metals would on their own. Steel has better strength, durability, low cost, high density, and high melting point than iron—all of which make it a very practical material for building and for creating everyday objects.
Why is Steel So Strong?
In iron, the structure of the actual atoms of the material are flexible, so the material gives away under pressure relatively easily. Atoms can glide around in many materials, even metals. This phenomenon is called dislocation. But, add a bit of carbon, and the iron molecules cannot move as easily. The material is hardened and can withstand much more pressure. In short, steel is so strong because the carbon atoms stop the iron atoms from moving past one another. The compromise is that steel is more rigid and less flexible than iron as a result.