Stainless steel or carbon steel? It is a question many plants, engineers, designers and other industry workers face at some point. Stainless and carbon steel pipes are both good choices for a variety of uses, so it may be hard to know which one is right. By getting down to the basics of what steel is and how it’s used, you should be able to better determine which will fit your needs.
You know that steel is a metal, for sure. You are aware that steel has many uses, and is found in so much of today’s fabricated world. However, even if you work with steel every day, it is possible that you have never stopped to consider what steel actually is. What is it made of? What makes steel different from other metals? And why are there so many types of steel?
What Is Steel?
Steel is a kind of metal called an alloy. An alloy is two or more kinds of natural metals that are melded together to make a new, unique metal. When we talk about steel, we are talking about a kind of metal alloy that is a mixture of iron and at least one other metal. Many types of steel have several metals in the mix, though how much is in there (that is, the concentration) may differ. Steels are classified by what kind of metals are in it and what kind of properties it has.
Carbon steel is a basic steel that is a combination of iron and carbon. It may contain other substances in trace or unmeasured amounts. Carbon steel is classified by how much carbon content is mixed in with the iron. A low-to-mid carbon steel will have less than 0.3% carbon, while a high carbon would contain up to 2%. Carbon steel is known for its strength and its ability to withstand very high temperatures.
Stainless steel is created by adding chromium to the alloy. While basic carbon steel may only contain up to 2% carbon, stainless steel has at least 10% chromium content. As with carbon steel, other elements may be present in stainless steel in unmeasured amounts. The most significant characteristic of stainless steel is that is doesn’t rust or corrode. Avoiding corrosion is a unique property for steel to have. Steel is mostly made of iron and iron tends to rust very quickly.
Other Types of Steel
There are many other types of steel, all with a variety of alloying elements (other metals in the mix). How the metals are heated and handled while they are being manufactured also determine a steel type and the properties it will have. Other elements found in steel could be tungsten, cobalt, nickel, lead and molybdenum.
Considerations for Steel Pipes
If you are trying to decide between stainless steel and carbon steel for your pipes, there are several factors to consider.
What is going in your pipes? What are they being created to carry? This is the first deal-breaking factor when deciding on a metal. Will it be carrying something corrosive, like chemicals or salt water? If so, you will want a metal that will not react as readily. This will usually mean choosing a stainless steel pipes, but double check the properties of the material you are working with to see what it reacts with.
Will your pipes be exposed to extreme temperatures? Carbon steel pipes are known for the ability to withstand high heats and is good for things like steam pipes. However, if you are working with extreme cold—for example, transporting cryogenic liquids—a different grade of pipe will be necessary.
Fortunately, both stainless steel and carbon steel can be very affordable. Carbon steel pipe is frequently ranked as the least expensive steel for piping, but stainless steel pipe is also usually right behind. This is good news, allowing you to choose the material that best fits the project without having to make significant cost considerations.
If your pipes will be visible and appearance is a consideration for you, knowing the finish of these steels will help. Stainless steel usually has a shine to it and holds up if exposed to weather and other elements. Carbon steel is darker and has a matte finish look. This may also start to corrode if exposed, deteriorating in appearance.
Your Steel Solution
Carbon steel pipes can be a very popular choice for a great variety of uses. Sewage pipes, municipal pipes, steam and vent pipes are often made of carbon steel. Consider what extra properties you might need—whether it be for temperature or chemicals. Those details will help you decide which steel is right for you.
The product statements contained herein are intended for informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness for a specific application or use. W. W. Grainger, Inc. does not guarantee the result of product operation or assume any liability for personal injury or property damage resulting from the use of such products.