What is 1018 Steel? Composition, Properties, and Uses

1018 steel is a mild, low-carbon steel with between 0.15-0.20% carbon content. The lower carbon content has a big impact making the steel easier to machine, shape, and weld without sacrificing overall strength or reliability. 1018 steel is a staple in everything from structural components to precision-machined parts.

1018 Steel Composition

1018 steel is a type of carbon steel, specifically classified as a low-carbon or mild steel. The carbon content in it ranges from 0.15% to 0.20%, which places it firmly in the that low-carbon category. That may seem minor, but it’s exactly what makes the material easy to machine and weld, while still offering solid tensile strength and durability.

Here’s a quick breakdown of 1018 steel’s chemical composition:

1018 Steel Properties

1018 steel is popular because it strikes a practical balance between strength, ductility, and workability. It’s not the strongest carbon steel out there, but it’s consistent, clean, and reliable (especially in cold-finished, or cold-rolled, form). 

This grade is known for excellent machinability and weldability, making it ideal for parts that require tight tolerances or high-volume processing. When cold drawn, it also offers improved surface finish and better dimensional control compared to hot-rolled steel.

While it won’t match the hardness of alloy steels, 1018 holds up well under moderate stress and can be surface hardened. Its performance makes it a top pick in both structural and precision-machined applications.

1018 Yield Strength

The yield strength of 1018 steel ranges from around 45,000 to 61,000 psi, depending on whether it’s hot or cold-rolled. Yield strength is the point where steel begins to permanently deform under stress. 1018 offers enough strength for structural and mechanical loads, while staying ductile enough for forming, machining, or welding.

1018 Tensile Strength

The tensile strength of 1018 steel typically falls between 55,000 to 78,000 psi, depending on the form and finish. This measures the maximum stress the steel can withstand before breaking. Cold-rolled 1018 offers the higher end of that range, making it a dependable choice for parts that need both strength and flexibility under load.

Density of 1018 Steel

The density of 1018 steel is approximately 0.284 lb/in³ (or 7.87 g/cm³). This is standard for most carbon steels and is useful when calculating weight per foot or planning material requirements.

What is 1018 Steel Used For?

1018 steel is used across a wide range of industries and applications where clean surface finish and tight dimensional tolerances matter. Some of the most popular applications of include:

• Shafts, pins, and axles
• Gears, studs, and fasteners
• Cold-formed parts and stampings
• Machined components and fittings
• Structural supports and framing
• Automotive parts
• Agricultural equipment
• Hydraulic and pneumatic components

1018 Steel FAQs

Is 1018 Low-Carbon Steel?

Yes, 1018 steel is classified as a low-carbon steel, with carbon content between 0.15% and 0.20%. This makes it easier to weld, shape, and machine compared to higher-carbon grades, without giving up basic strength and reliability.

Can 1018 Steel Be Hardened?

Yes, 1018 steel can be surface hardened through case-hardening methods. This creates a hard exterior while keeping the core tough and ductile, which is ideal for wear-resistant applications like gears or pins.

What’s the Difference Between A36 Steel vs. 1018?

The main difference between 1018 steel and A36 steel is consistency and form. A36 is a structural-grade steel with broader specs, often hot-rolled, while 1018 is a more precise, low-carbon steel that’s typically cold-rolled for tighter tolerances and better surface finish. 

Get High-Quality 1018 Steel for Your Projects!

1018 steel is a low-carbon, versatile steel grade that’s trusted for one simple reason: it works. It machines cleanly, welds easily, and offers just the right amount of strength for a wide range of jobs. Whether you’re running high-volume machining or fabricating structural components, 1018 steel is a go-to material for consistent performance.

Service Steel has built a reputation on premium quality and exceptional service. We ensure that every steel product meets rigorous ASTM steel standards and exceeds expectations. Explore our extensive inventory of structural steel, all ready-to-ship for your projects. Request a free quote or give us a call today!