6 Most Common Structural Steel Materials (and Their Uses)

Structural steel has shaped construction for centuries. It offers unmatched strength, versatility, and durability—qualities that make it the backbone of modern building projects.

Today, advancements in metallurgy give builders access to several distinct steel construction materials, each designed for specific roles.

Here are the six most common structural steel materials and where you’ll see them used in modern construction.

1. Carbon Steel

Carbon steel is the most widely used type of steel, making up 85% of global steel production.

It’s made primarily of iron and carbon, with carbon content ranging from 0.12% to 2.0%. That percentage matters—because the higher the carbon, the stronger the steel, but the trade-off is reduced ductility.

• Low-carbon steel (mild steel): Easier to shape and weld, commonly used in construction frames and reinforcing bars.

• Medium-carbon steel: Balances strength and ductility, often found in machinery and automotive parts.

• High-carbon steel: Extremely strong but less flexible, making it ideal for heavy-duty applications like bridges, rails, and cutting tools.

Carbon steel is also highly cost-effective. Since it’s made with inexpensive elements, it delivers strength and versatility without driving up project budgets.

Common Uses:

• Building frames and structural beams

• Bridges and overpasses

• Reinforcing bars (rebar)

• General infrastructure projects

2. Galvanized Steel

Galvanized steel is carbon steel coated with a protective layer of zinc.

This coating acts as a barrier against moisture, oxygen, and other environmental factors, giving the steel excellent resistance to rust and corrosion.

One of its biggest advantages is low maintenance—the zinc coating greatly extends the lifespan of steel used in outdoor or exposed applications.

Because of these properties, galvanized steel is one of the most common steel building materials in both residential and commercial projects.

Common Uses:

• Roofing and siding panels

• Structural beams and framing

• Fencing, guardrails, and outdoor structures

3. Alloy Steel

Alloy steel begins as carbon steel, but with added elements such as chromium, nickel, manganese, vanadium, or molybdenum.

These alloying elements transform its performance, giving manufacturers the ability to fine-tune strength, toughness, and resistance to heat, wear, or corrosion.

Because its composition can be tailored to specific needs, alloy steel is often considered a specialty material—built to thrive in high-stress or extreme environments where reliability is critical.

Many alloy steels are further enhanced through processes like quenching and tempering, which increase their strength and toughness for use in heavy machinery, cranes, and construction equipment.

Common Uses:

• Oil and gas pipelines

• Automotive components like gears and shafts

• Industrial machinery and power plant equipment

4. High-Strength Low-Alloy (HSLA) Steel

HSLA steel is made with less carbon than regular carbon steel (usually under 0.25%) but includes small amounts of copper, nickel, niobium, or vanadium.

This careful balance keeps it light and workable while greatly improving its strength, toughness, and resistance to corrosion.

That unique composition makes HSLA ideal for projects where engineers need maximum strength without adding weight. It’s this property that has made HSLA steel a backbone of modern bridges, skyscrapers, and heavy equipment, allowing builders to achieve designs that would be impossible with standard carbon steel.

Common Uses:

• Shipbuilding

• Cranes and heavy construction machinery

• Large-span bridges and towers

5. Stainless Steel

Stainless steel is made with at least 10.5% chromium, and often includes nickel, molybdenum, or nitrogen as well. The chromium is what makes stainless unique—it forms a thin oxide film on the surface that blocks moisture and oxygen, preventing rust.

Its composition makes stainless steel not only durable but also visually appealing, which is why it’s so common in both construction and design.

And while it costs more upfront than other steels, its low maintenance and long lifespan often make it the most cost-effective choice in harsh or corrosive environments.

Common Uses:

• Coastal and marine structures

• Water treatment facilities

• High-rise facades and architectural features

6. Weathering Steel (Corten)

Weathering steel is primarily carbon steel with small amounts of copper, nickel, and chromium.

These added elements allow it to form a stable, rust-like patina when exposed to air and moisture. That outer layer seals and protects the inner steel, preventing deeper corrosion.

Its chemical makeup makes it a favorite for architectural designs and outdoor structures where both durability and appearance matter.

Because it doesn’t require paint or coatings, weathering steel also reduces maintenance costs over a structure’s lifetime—a major reason it’s so widely used in bridges and large-scale public projects.

Common Uses:

• Outdoor sculptures and monuments

• Pedestrian and highway bridges

• Building facades and exposed structures

Overview of Common Steel Materials

Conclusion

Each type of structural steel brings its own strengths to construction.

Carbon steel remains the foundation of most projects, valued for its affordability and versatility. Galvanized steel adds long-lasting protection in exposed environments, while alloy and HSLA steels deliver higher performance where strength and reliability are critical. Stainless steel combines durability with design appeal, and weathering steel offers a unique balance of toughness and aesthetic character.