Why Is Stainless Steel Stainless?

steel bars

steel barsYou probably know that stainless steel is a good choice when you want something that is strong but will not rust. Many types of stainless steel are available, and you might get confused about what to get.

When you get your steel supply online, the supplier can probably help you pick the best one if you tell them about your needs. However, it would be good to know why stainless steel is stainless, and why your supplier recommends a certain grade of stainless steel.

What It Is

All steel alloys are mainly made of iron. What makes it different from other types of steel alloys is that it has high amounts of chromium and nickel instead of carbon. This is why it is called a high-alloy metal. It holds up better against rust and heat than other steel alloys. The different types of steel metal depend on what other alloys are present to make it stronger or easier to weld. However, all stainless steel is rust resistant because of the chromium.

How It Works

We know that iron rusts when exposed to air and water for a bit. After a while, you see flakes and crusts forming on the surface that easily break off, and soon enough you will not have anything left. This is where chromium comes in.

All types of stainless steel have at least 10.5% chromium. The important thing to know about chromium is how it reacts to oxygen and water. It forms a very thin protective film called an oxide on the surface. Any steel that has at least 10.5% chromium will get the benefit of this protective film, which keeps the oxygen from reacting any more to the iron so it will not rust. It does not react to anything else once it is set.

How It Keeps Working

The remarkable thing about chromium oxide is that it regenerates, just like magic. When you use steel wool on a stainless steel pan, for example, the protective film comes off. However, the chromium creates another protective film as a reaction to exposure to the air. This is why good quality stainless steel is such a good idea for cutlery.

Even if you do not plan to eat with it, stainless steel is a good material for anything that you want to keep for a long time. You do not have to do much to keep it in good condition except keep it clean and let the chromium do the rest.