A588 Steel Properties, Strength, & Uses

November 24, 2025 | Categorized in: Types

A588 steel is a popular steel grade in the construction and structural industries. As a high-strength, low-alloy steel designed for outdoor environments, it has exceptional durability and longevity.

A588 Steel Composition

Like A36 steel, A588 is a low-carbon grade with a max carbon content of 0.19% (Grade A). However, alloying elements like copper, chromium, and nickel boost its corrosion resistance, as well as offering high yield and tensile strength.

Here’s a quick breakdown of A588 steel’s composition:

A588 Steel vs. A36

A588 steel has a higher yield strength and tensile strength than A36 steel. It’s also harder, meaning that it resists indentation more than A36 steel. While A36 typically requires a coating like galvanization for corrosion resistance, A588 steel is known as a “weathering steel” because it forms a copper-enhanced patina that can improve corrosion resistance without requiring a separate coating. These properties generally come with a higher price tag than A36.

A588 Steel Properties

A588’s atmospheric corrosion resistance is one of its most well-known selling points. This primarily comes from the stable, rust-like layer that forms on its surface when exposed to the elements. As we’ll discuss below, it also has high strength and durability, which makes it ideal for structural applications like buildings and bridges.

A588 Yield Strength

The yield strength of A588 steel is approximately 50,000 psi. In simpler terms, this means that A588 grade steel can resist 50,000 pounds per square inch of stress before it begins to deform permanently. For structural steel, this level of strength makes A588 ideal for architectural facades, building frames, railcars, and other applications that need to remain stable and withstand outdoor elements with minimal maintenance.

A588 Tensile Strength

A588 steel typically has a tensile strength ranging from 70,000 to 90,000 psi. This refers to the point at which the material will break under tension (pulling or stretching). This broad range gives A588 flexibility across different applications, allowing it to handle both static and dynamic forces in construction and industrial settings.

A588 Steel Hardness

A588’s Brinell hardness, which measures a material’s resistance to indentation, generally ranges from 135 to 170. This is another characteristic that makes it a strong choice for demanding structural applications that require high deformation resistance.

A588 Steel Density

The density of A588 steel is approximately 0.282 pounds per cubic inch. This is standard for carbon steels and makes it easy to estimate weight, load capacity, and shipping requirements when planning structural or mechanical projects.

A588 Steel Melting Point

A588 steel has a melting point of 2,700°F, or 1,480°C. This melting temperature is characteristic of most low-carbon steels and ensures that A588 can be safely welded, heat-treated, or used in high-temperature environments without losing structural integrity.

What is A588 Steel Used For?

As we’ve discussed, A588 steel is mostly used in outdoor applications where its “weathering steel” moniker can shine. This, paired with its high strength, makes it a great option for structural projects where long-term durability and minimal maintenance are desired. Common examples of A588 applications include:

• Bridge girders, decking, and supports
• Building frame components like beams, columns, and bracing
• Highway guardrails and other infrastructure
• Utility poles
• Outdoor sculptures

A588 Steel FAQs

What does A588 steel mean?

A588 steel gets its name from the ASTM (American Society for Testing and Materials) specification that governs it: ASTM A588. This specification outlines the material’s required chemical composition and mechanical properties. It’s one of the most commonly used steel grades for structural applications in the United States.

• The “A” indicates that this is a ferrous (iron-based) metal
• The number “588” refers to its specific ASTM designation number

Can you weld A588 steel?

Yes, A588 steel can be welded. In fact, this is often the primary method used for joining A588 components like beams. However, use proper welding techniques and filler materials to ensure both a strong joint and matching corrosion resistance (so weak points aren’t created).

Can A588 be galvanized?

Yes, A588 steel can be galvanized. While it’s known for its natural environmental resistance, galvanizing this grade can provide even more thorough corrosion resistance for extreme environments.

Is A588 machinable?

Yes, A588 steel has good machinability. While some metals that have high strength and corrosion resistance aren’t ideal for machinability, A588 can be cut, shaped, drilled, and welded. However, note that this grade still requires some expertise to machine due to its high-strength nature.

Looking for a High-Quality A588 Steel Supplier?

A588 steel is a fantastic steel choice for outdoor structural applications, but it has a variety of uses beyond this primary category. If you need A588 structural steel products for an upcoming project (or think it might be a good fit), contact Service Steel Warehouse today. Explore our extensive inventory of structural steel, all ready-to-ship for your projects. Request a free quote or give us a call today!