CDM Systems, Inc. > Resources > Blog > Mild Carbon Steel vs. AR Steel vs. Stainless Steel: What’s the Right Steel for You?

What’s the Right Steel for You?

The good thing about customizable process flow systems for bulk material handling is the freedom to make sure the equipment is a perfect fit.

The tricky part is figuring out the perfect fit.

With so many options, it gets overwhelming if you aren’t an expert. It’s like standing in the toothpaste aisle deciding between hundreds of brands.

Let’s make it simpler and look at one aspect of the decision process:

Should you use mild carbon steel, abrasion-resistant (AR) steel or a form of stainless steel for your gates, valves and diverters?

Carbon Steel

Mild Carbon Steel: Carbon steel has a higher carbon content (duh) – around 0.05 to .25 percent of its weight. The upside of mild carbon steel is it’s stronger and harder than other forms of steel. This comes in handy if you’re dealing with mild to moderately abrasive materials or high temperatures.

However, mild carbon steel is more susceptible to rusting and corrosion if exposed to heavy moisture. It’s strength and hardness also mean it’s less malleable than other steels – making it more likely to crack when under extreme stress.

Mild carbon steel is a great choice if you handle dry and non-corrosive materials (such as grains, rice, frac sand, etc.) and the surrounding area of your plant doesn’t have a lot of moisture

For example, mild carbon steel is a good choice if you run a rice plant in California or a grains facility in Colorado.

Abrasion-resistant steel: Abrasion-resistant steel is a high-carbon steel that’s been hardened. AR steels feature the strength from adding carbon along with a resistance to oxidization from added alloys.

This best-of-both-worlds combination results in a steel that is somewhat in the middle: Not quite as strong as carbon steel but better resistance to rusting. Not quite as resistant to rusting as stainless steel, but also stronger and harder.

How much is it AR steel hardened?

Well, on the Brinell scale – which measures the hardness of steel, with the higher the number meaning the harder it is – mild carbon (130-160BHN) and stainless steel (160-200BHN) are relatively similar. AR steel tends to come in between 235-550BHN.

AR steels are a great choice to build a gate, valve or diverter if you deal with high abrasive, low corrosive materials.

This could be a solid option if, for example, you run a quarry in Indiana or handle cement in Minnesota.

Stainless Steel

Stainless steel’s strengths and weaknesses are somewhat a mirror image of carbon steel.

It doesn’t rust because it’s protected against the oxidation process because it contains at least 10.5% of chromium. Therefore, the outer layer of chromium protects it against rusting. However, it’s not as strong as carbon steel.

(Quick science lesson: oxidation is a chemical transformation when the steel changes its properties when it’s exposed to oxygen, causing it to rust.)

Stainless steel is a great choice if the material you handle is moist or corrosive with low abrasive properties (such wet fly ash, gravel, fertilizer, etc.) and/or the surrounding area of your plant could have a lot of moisture.

For example, it’s a good option if you run a fertilizer plant in Mississippi or handle petroleum coke in a wet outdoor environment like Oregon.

But the most important thing…

No matter the steel, find a conveyor system manufacturer that works hand-in-hand with you throughout the process. A knowledgeable and experienced partner could be a major influence in purchasing the perfect gate, valve and diverter.

CDM understands that one-size-fits-all is a recipe for disaster. That’s why we make our equipment custom-ordered, only after we understand the needs of your facility. There are a lot of factors that make up the perfect fit for your specific plant.

Let us help you find it.


About CDM

The CDM story is about recognizing every industrial operation is different, as are their conveying challenges. A custom-engineered conveying system is a cost-effective approach to any operation willing to look at the value of having a partner who is vested in your success and one who stands by their product. CDM has earned more than 91 percent repeat business because we’re more than just a conveying systems manufacturer – we’re a business partner. 

For further information contact:

Andrew Parker, President CDM Systems, Inc.  •