Alloy Steel vs Carbon Steel: Which One is Right for Your Project?

Are you stuck trying to pick between alloy steel and carbon steel? Many makers face this same problem. Picking the wrong steel can cost you money, time, and might even make your parts fail. This is a big issue that can hurt your whole project.

When you pick the wrong steel type, things can get worse. Parts might break too soon. They might rust. They might not work in hot places. Your costs might go up. These problems can make your whole project stop.

At Istar Machining, we help solve this problem. We know both steel types well. Our experience helps you pick the right steel for each job. We will show you all about both steel types so you can make a good choice.

What is Carbon Steel?

Carbon steel is a mix of iron and carbon. It has 0.05% to 2.1% carbon with not many other things added. Think of it as a simple steel.

Types of Carbon Steel:

• Low-carbon steel (mild steel): Bends well, easy to weld
• Medium-carbon steel: Good balance of strength and work-ability
• High-carbon steel: Very hard, good for tools

Carbon steel is strong and does not cost much. But it can rust easy and does not work well in very hot places.

What is Alloy Steel?

Alloy steel starts with iron and carbon too. But then we add more stuff like chromium, nickel, or molybdenum. These extras make the steel work better in tough spots.

At Istar Machining, we often use alloy steel for our precision CNC machining work when parts need to be extra strong or work in harsh places.

What Gets Added to Alloy Steel:

• Chromium: Helps fight rust
• Nickel: Makes it stronger
• Molybdenum: Helps it stay strong when hot
• Manganese: Makes it harder

Alloy steel costs more than carbon steel. But it works better in tough spots like very hot places or wet places.

Steel Types Side by Side

Here is how they stack up:

Big Differences in How They Work

Strength

Carbon steel can be strong, with some types having up to 1,500 MPa tensile strength. But alloy steel can get even stronger, up to 2,000 MPa. This is why we at Istar Machining often use alloy steel for our custom CNC machining jobs that need extra strength.

Rust Fighting

Carbon steel rusts easy. If you put it outside, it will start to rust. You need to paint it or coat it.

Alloy steel with chromium fights rust much better. Some types with lots of chromium can stay outside for a long time with no rust.

Heat Fighting

This is a big one. Carbon steel gets weak when it gets hot – above 250°C it starts to lose strength[^3]. But alloy steel can stay strong up to 600°C. For hot parts, we always use alloy steel in our steel CNC machining work.

Easy to Work With

Carbon steel is easy to cut, bend, and weld. Low-carbon steel is the easiest.

Alloy steel can be harder to work with. It might need special tools or skills. At Istar Machining, we have the right tools and know-how to work with all types of alloy steel.

Cost

Carbon steel costs less. Low-carbon steel costs about $500-$800 per ton. High-carbon costs $800-$1,200 per ton.

Alloy steel costs more – from $1,000 to over $2,000 per ton[^2] for high-alloy types.

When to Use Each Type

When to Use Carbon Steel:

• Building frames and beams
• Pipes that won’t get too hot
• Machine parts that won’t get wet
• Projects with tight budgets
• Simple parts

Our CNC milling team works with carbon steel when the job does not need the extra traits of alloy steel.

When to Use Alloy Steel:

• Plane parts
• Car gears and engine parts
• Oil rig parts
• Parts that will get very hot
• Parts that might rust
• Parts that must not fail

With our CNC prototype machining service, we can test both steel types to see which works best for your new designs.

5 Things to Think About When Picking Steel

1. Where will it go? Will it get wet or hot?
2. How much weight will it hold? Do you need extra strength?
3. How much can you spend? Alloy costs more.
4. How will you make it? Some steels are harder to work with.
5. Do you need to follow rules? Some jobs have strict rules about what steel to use.

Real World Steel Picks

Here are some real examples of when to pick each type:

Pipeline Project: A gas company picked ASTM A53 carbon steel for their pipes. It was strong enough and cost less than alloy steel. The pipes were coated to stop rust.

Plane Landing Gear: A plane maker picked 4340 alloy steel (with nickel, chromium, and molybdenum). It needs to be super strong and not fail. The extra cost was worth it for safety.

At Istar Machining, we’ve helped many clients pick the right steel for their projects. Our precision CNC machining team can guide you through the whole process.

Common Questions About Steel Types

How We Help at Istar Machining

At Istar Machining, we know steel. Our team has years of work with both carbon and alloy steel. We can help you pick the right type for your job.

Our CNC machining service can work with all types of steel. We have the right tools and skills to make parts from any steel type you need.

We can even help test both types to see which works best for your job. Our team will work with you to find the best mix of cost, strength, and other things you need.

The Bottom Line on Steel Types

Picking between carbon steel and alloy steel is a big choice. Here’s what to remember:

• Carbon steel is cheaper and easier to work with. It’s good for simple jobs where you don’t need special traits.
• Alloy steel costs more but works better in tough spots. It’s stronger, fights rust better, and handles heat better.

The best pick depends on your job. Think about where the part will go, what it needs to do, and how much you can spend.

Need help with your steel parts? Contact Istar Machining today. We’ll help you pick the right steel and make the parts you need.