Carbon steel is a widely used material that is vital to many industries due to its unique properties.
Some of the most common types of carbon steel include low-carbon steel, medium-carbon steel, high-carbon steel, and ultra-high carbon steel.
Mild steel has less than 0.25 wt.% carbon and cannot be hardened by heat treatment to form martensite.
Medium carbon steel contains 0.25 to 0.60 wt.% carbon and 0.60 to 1.65 wt.% manganese.
High-carbon steel contains 0.60 to 1.25 wt.% carbon and 0.30 to 0.90 wt.% manganese.
Carbon steel is the backbone of modern industry. From the skyscrapers that shape our cities to the cars we drive every day, its strength and versatility are unquestionable. But not all carbon steels are created equal. Selecting the right grade is critical to a project’s safety, longevity, and cost-effectiveness.
However, navigating the world of carbon steel grades—including names like low carbon, medium carbon, and high carbon, as well as specific codes like A36 or 1018—can be challenging.
This comprehensive guide aims to make that process easier. We’ll walk you through the different categories, compare their properties, and help you choose the best carbon steel grade for your specific application.
What Exactly is Carbon Steel?
At its core, carbon steel is an iron alloy where carbon is the main alloying element. While other elements like manganese and silicon are present in small quantities, it is the carbon content that primarily determines the steel’s properties.
A simple rule to remember is:
Higher Carbon Content = Higher Hardness & Strength, Lower Ductility & Weldability.
Lower Carbon Content = Higher Ductility & Weldability, Lower Hardness & Strength.
This trade-off is the key to understanding the three main categories of carbon steel.
Carbon Steel Grades Chart: The Most Popular Grades and Uses
Brief explanation of the importance of carbon steel in various industries.
Purpose of the chart: to provide a quick reference for common carbon steel grades and their applications.
Low-carbon steel Grades
Carbon Content: Typically 0.04% to 0.30%
This is the most common and widely used type of carbon steel. Its low carbon content makes it highly ductile, easy to weld, and simple to machine. While it doesn’t possess the high strength of other grades, its excellent formability and low cost make it a top choice for a vast range of applications.
Key Properties: Excellent weldability, high ductility, good impact strength, and low cost.
Common Applications: Structural beams (steel plates and shapes), automotive body panels, pipes, food cans, and everyday construction materials.
| Grade | Carbon Content | Common Uses |
|---|---|---|
| ASTM A36 | 0.26% – 0.29% | Structural applications, general fabrication |
| SAE 1008 | 0.10% max | Cold-formed components, automotive panels |
Medium Carbon Steel Grades
Carbon Content: Typically 0.31% to 0.60%
Medium-carbon steel strikes a balance between the ductility of low-carbon steel and the strength of high-carbon steel. The increased carbon content makes it stronger, harder, and more resistant to wear. It is often further strengthened through heat treatment processes like quenching and tempering.
Key Properties: Good balance of strength and ductility, good wear resistance, suitable for heat treatment.
Common Applications: Railway tracks, gears, crankshafts, axles, machinery parts, and high-pressure pipes.
| Grade | Carbon Content | Common Uses |
|---|---|---|
| AISI 1045 | 0.43% – 0.50% | Shafts, machinery parts, automotive components |
| EN 8 | 0.35% – 0.45% | Gears, studs, bolts |
High-Carbon Steel Grades
Carbon Content: Typically 0.61% to 1.50%
Known for its exceptional hardness and strength, high-carbon steel is the toughest of the three. This hardness, however, comes at the cost of ductility, making it brittle and difficult to weld, cut, or form. It is almost always hardened and tempered.
Key Properties: Very high strength, exceptional hardness, and wear resistance.
Common Applications: Cutting tools (drills, blades), high-strength springs, strong wires, and dies.
| Grade | Carbon Content | Common Uses |
|---|---|---|
| AISI 1095 | 0.90% – 1.03% | Springs, cutting tools, knives |
| EN 9 | 0.50% – 0.60% | High-stress components, axles |
Alloyed Carbon Steel Grades
| Grade | Alloying Elements | Common Uses |
|---|---|---|
| AISI 4140 | Chromium, Molybdenum | Shafts, gears, and automotive components |
| ASTM A572 | Vanadium, Columbium | Structural steel in construction |
Carbon Steel Grades: A Quick Comparison Chart
| Grade Type | Carbon Content (%) | Key Properties | Common Applications | Weldability |
| Low-Carbon | 0.04% – 0.30% | Very ductile, easy to form, excellent weldability, lower strength. | Structural steel, car bodies, pipes, plates. | Excellent |
| Medium-Carbon | 0.31% – 0.60% | Balanced strength & ductility, good wear resistance. | Gears, axles, machinery parts. | Fair (requires preheating) |
| High-Carbon | 0.61% – 1.50% | Extremely hard and strong, with high wear resistance, and brittle. | Cutting tools, springs, and high-strength wire. | Poor (not recommended) |
Need to source high-quality carbon steel for your project? Huaxiao Metal provides a full range of certified carbon steel products.
Learn More About Common Carbon Steel Grades
Beyond the general categories, specific grades are designated by standards organizations like ASTM and AISI. Here are a few of the most common ones you’ll encounter:
ASTM A36 Steel
A classic example of low-carbon steel, A36 is arguably the most common structural steel in the world. It offers good strength combined with excellent formability and weldability, making it a reliable and cost-effective choice for general construction.
Common Uses: Building frames, bridges, platforms, and manufacturing structural steel plates.
AISI 1018 Steel
AISI 1018 is another popular mild/low-carbon steel that provides a good balance of toughness, strength, and ductility. It is well-suited for machining and forming processes and offers excellent weldability.
Common Uses: Shafts, spindles, pins, rods, and other machine parts that don’t require extreme strength.
AISI 1045 Steel
This is a popular grade of medium-carbon steel. It offers higher strength and hardness than the 1018 grade and responds very well to heat treatment. It’s an excellent choice for parts that need to withstand more wear and tear.
Common Uses: Gears, axles, bolts, studs, and parts requiring higher strength and impact resistance.
How to Choose the Right Carbon Steel Grades for Your Project
To make the right choice, ask yourself these four key questions:
What Mechanical Properties Are Required? Do you need extreme strength and hardness (high-carbon), or is it more important for the material to be ductile and easy to form (low-carbon)?
Will It Be Welded? If your project involves significant welding, low-carbon steel like A36 or 1018 is your best and safest option.
Does It Need to Be Machined? While all carbon steels can be machined, low-carbon grades are generally easier to work with, extending tool life.
What Are the Environmental Conditions? Remember that carbon steel is susceptible to rust. If it will be exposed to moisture, you must plan for a protective coating like paint or galvanization.
Carbon Steel Grades For Sale From China Carbon Steel Suppliers
1010 Steel
1010 Steel – Your Trusted Supplier for Sheet, Plate, Coil & Bar 1010 Carbon Steel is a widely used low-carbon steel known for its excellent
1008 Steel
1008 Steel – Premium Low Carbon Steel from Huaxiao Metal 1008 steel is a common low-carbon steel with excellent weldability and formability, making it ideal
1075 Steel
AISI 1075 Steel Suppliers and Manufacturer 1075 carbon steel is a high carbon steel material known for its excellent strength, hardness, and wear resistance. It
Q345 Steel
Material Q345 Steel Suppliers and Manufacturer Huaxiao Metal is a renowned name in the metal manufacturing and export industry, boasting over a decade of expertise
1060 Steel
AISI 1060 Steel Suppliers and Manufacturer (UNS G10600) 1060 Carbon Steel Available Products Round Bar Flat Bar Square Bar Hexagon Bar Plate Coil and More
A36 Carbon Steel
A36 Carbon Steel Suppliers and Manufacturer A36 grade carbon steel is easy to weld, form, and form using machine tools. They have a good strength-to-weight
5160 Steel
AISI 5160 Steel Suppliers and Manufacturer 5160 High Carbon Steel Available Products Round Bar Flat Bar Square Bar Hexagon Bar Plate Coil Tube and More
1095 Steel
AISI 1095 Steel Suppliers and Manufacturer 1095 Steel is a high carbon steel that is widely used for its excellent hardness, edge retention and durability,
1080 Steel
AISI 1080 Steel Suppliers and Manufacturer Trusted AISI 1080 Steel Supplier and Manufacturer – Huaxiao Metal If you are looking to buy AISI 1080 steel,
1018 Steel
AISI 1018 Steel Suppliers and Manufacturer 1018 Carbon Steel Available Products Round Bar Flat Bar Square Bar Hexagon Bar Plate Coil Tube and More Please
1040 Steel
AISI 1040 Steel Suppliers and Manufacturer Looking for a reliable AISI 1040 steel supplier for your project? At Huaxiao Metal, we specialize in high-quality AISI
1045 Steel
AISI 1045 Steel Suppliers – Huaxiao Metal 1045 carbon steel is a medium carbon steel grade known for its excellent strength, toughness, and wear resistance.
4140 Steel
Alloy AISI 4140 Steel Suppliers (UNS G41400) Your trusted supplier for high-tensile 4140 steel in bar, plate, sheet, and custom-cut forms. Known for its exceptional toughness,
Frequently Asked Questions
Does carbon steel rust?
Yes. The iron in carbon steel oxidizes when exposed to oxygen and moisture, creating iron oxide (rust). To prevent this, carbon steel parts must be protected with paint, galvanization, or another surface coating.
What standards do you supply for carbon steel?
We supply carbon steel that meets a wide range of international standards, including ASTM, AISI, SAE, EN, DIN, and JIS, ensuring you receive material that complies with your project’s requirements.
What is the main difference between carbon steel and stainless steel?
The key difference is the presence of chromium. Stainless steel contains at least 10.5% chromium, which creates a passive, corrosion-resistant layer on its surface. Carbon steel does not have this layer and will rust if not protected.
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