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.
The Types of Steel
Adding other metals to steel, creating it in different ways, and adding different finishing treatments can all change the strength of steel or make it a more useful material in other ways. Although steel is not the strongest metal in its most basic form, advanced forms of steel that have heat-treatments can be stronger and harder than the hardest metals (such as Titanium).
There are threebasic types of steel you hear about most commonly:
- Carbon steel: This is steel that has only carbon added to it. The amount of carbon can vary widely, from 0.002% to 2.14%. More carbon means more strength, but also more brittleness.
- Alloy steel: All steel is an alloy, but we call steel that has a third substance (usually a metal) added to it alloy steel. There are a wide range of metals we can add to steel to get different properties. For example, we may add nickel for more strength and stability.
- Stainless steel: Stainless steel is a sub-type of alloy steel. It is specifically steel with chromium added. Chromium prevents the steel from rusting.
You may also hear of hot-rolled and cold-rolled steel. These are not types of steel, but ways to manufacture it.
What Form of Steel is Best for My Cable Railing?
Of all the kinds of steel we could use for our cable railings, we prefer to use marine-grade stainless steel cable. This type of steel is highly resistant to corrosion, as other stainless steels are. Marine-grade means that it has undergone special treatments to better withstand being submerged in water or being close to bodies of water. Your railing won’t be submerged—but it will be exposed to water from time to time, and we want it to stand up to this challenge easily.
