What's the difference between Corten and A606 Weathering Steel?

Mason Buchette
Feb 24
3 min read

Looking for a roofing or siding material that offers a unique aesthetic, exceptional durability,

and a story to tell? At True Metal Supply, we're excited to introduce you to A606 Weathering Steel – the modern solution for achieving that coveted, naturally rusted look in architectural design.

Often admired for its rich, earthy tones and industrial elegance, A606 steel isn't just a trend; it's a testament to materials that get better with age.

What is A606 Weathering Steel?

A606 is a high-strength, low-alloy steel specifically engineered to develop a stable, protective rust-like patina when exposed to the elements. Unlike ordinary steel that corrodes away, A606's unique chemical composition allows it to form a barrier of rust that actually slows down further corrosion, giving it remarkable longevity and a distinctive appearance.

Imagine your home or business adorned with panels that start out looking like regular steel, then gradually transform into a beautiful tapestry of orange, brown, and deep red hues. That's the magic of A606.

A606 vs. Corten: Clearing Up the Confusion

You've probably heard the term "Corten" when discussing weathered steel. While often used interchangeably, it's important to understand the distinction, especially when purchasing for roofing and siding applications:

Corten is a brand name (a registered trademark of U.S. Steel) for a specific family of weathering steels. It was one of the first and most widely recognized weathering steels.
A606 Type 4 is the ASTM (American Society for Testing and Materials) specification that defines the chemical composition and mechanical properties for thin-gauge (typically 22 gauge and 24 gauge) weathering steel sheet and coil.

In essence, when you're looking for "Corten" for your metal roofing or siding project, A606 Type 4 is the modern, industry-standard material you'll be using. It provides the same aesthetic and protective qualities as the original Corten, optimized for architectural panels.

Why Choose A606 Weathering Steel for Your Project?

Unique, Evolving Aesthetic: No two A606 installations are exactly alike. The patina develops naturally, creating a one-of-a-kind look that changes and deepens over time. It's perfect for achieving rustic, industrial, or modern farmhouse aesthetics.
Exceptional Longevity: Designed to last 40-60 years (or even longer in ideal conditions), A606 forms its own protective layer, eliminating the need for painting or regular maintenance associated with traditional painted metals.
High Strength & Durability: A606 offers superior tensile strength compared to standard carbon steel, providing excellent resistance to harsh weather, impacts, and high winds.
Eco-Friendly: Made from steel, A606 is a recyclable material, aligning with sustainable building practices.

Important Considerations Before You Buy

While A606 is incredible, it's crucial to be aware of a few characteristics:

Rust Runoff: As the patina forms, rain will carry small amounts of rust particles. This will stain lighter-colored surfaces like concrete, stucco, and stone walkways below. Plan your landscaping and drainage accordingly.
Optimal Environment: A606 performs best in environments with distinct wet and dry cycles, allowing the patina to dry and stabilize. It's generally not recommended for coastal areas with constant salt spray or regions with persistent high humidity.
Proper Installation: Avoid areas where water can consistently pond or where debris can trap moisture, as this can prevent the protective patina from forming correctly and lead to premature corrosion.

Ready to Embrace the Beauty of A606?

At True Metal Supply, we stock high-quality A606 Weathering Steel panels and coils, perfect for standing seam roofs, corrugated siding, accent walls, and more. Our experts can help you understand if A606 is the right choice for your project and guide you through the selection process.

Contact us today or visit our showroom to learn more about A606 Weathering Steel and discover how it can transform your next building project!

Get a Quote on A606 Weathering Steel