When ordering structural steel, one of the most common questions buyers ask is whether they should choose A36 or A572 steel. Both are widely used, readily available, and suitable for many structural applications — but they are not the same.
Understanding the differences in strength, performance, availability, and cost helps ensure you specify the right grade for your project, avoid unnecessary expense, and prevent delays.
This guide breaks down A36 vs A572 steel in clear, practical terms so you can make the best decision.
What Is A36 Steel?
A36 is one of the most common structural carbon steels used in the United States. It has been a go-to material for decades because it is:
- Easy to weld
- Easy to machine
- Widely available
- Cost-effective
A36 is often used for beams, plates, angles, channels, base plates, brackets, and general fabrication. It has a minimum yield strength of 36,000 psi, which makes it suitable for many light-to-moderate structural loads.
What Is A572 Steel?
A572 is a high-strength, low-alloy (HSLA) structural steel. It was developed to provide higher strength with less material, allowing engineers to design lighter, stronger structures. A572 comes in multiple strength grades, with Grade 50 being the most commonly used in construction. A572 Grade 50 has a minimum yield strength of 50,000 psi, which is significantly higher than A36.
Key Differences Between A36 and A572
| Feature | ASTM A36 | ASTM A572 (Grade 50) |
|---|---|---|
| Yield Strength | 36,000 psi (36 ksi) | 50,000 psi (50 ksi) |
| Steel Type | Carbon Steel | High-Strength Low-Alloy (HSLA) |
| Weldability | Excellent / Very Forgiving | Excellent (Requires proper procedure) |
| Primary Use | General Fabrication / Light Duty | Structural Frames / Heavy Loads |
Strength and Yield
A36 steel has a yield strength of 36 ksi, meaning it begins to permanently deform at lower loads. A572 Grade 50 has a yield strength of 50 ksi, making it about 40 percent stronger than A36. This higher strength allows engineers to use less steel while maintaining the same structural capacity.
Chemical Composition
A36 is a simple carbon steel. A572 contains small amounts of alloying elements such as manganese, niobium, or vanadium that increase strength without sacrificing weldability. These alloying elements are what make A572 stronger and more efficient in structural applications.
Weight and Structural Efficiency
Because A572 is stronger, it can often be used in smaller sizes than A36 to carry the same load. That means:
- Lower total steel weight
- Easier transportation
- Reduced erection loads
- Potential savings in foundations and framing
Weldability and Fabrication
Both A36 and A572 weld very well using standard welding methods. A36 is slightly more forgiving for low-skill welding or dirty/imperfect conditions. A572 requires proper welding procedures but performs just as well when welded correctly.
Typical Use Cases
A36 is commonly used for:
- Base plates
- Light beams and columns
- Brackets and plates
- General fabrication
- Non-critical structures
A572 is commonly used for:
- Structural beams and columns
- Bridges
- Commercial buildings
- High-load steel frames
- Projects where weight and strength matter
Cost and Availability Considerations
A572 typically costs more per pound than A36. However, because A572 is stronger, many projects use less steel, which can lower the total installed cost. In large buildings and bridges, A572 often ends up being the more economical choice. For small fabrication jobs, A36 may be the better value.
A36 is stocked almost everywhere and is rarely difficult to source. A572 Grade 50 is also widely available, but certain sizes may have longer lead times or specialty shapes may need to be ordered. Always confirm availability before finalizing your project design.
Can A572 Replace A36?
In many cases, A572 Grade 50 can substitute for A36, but the reverse is not always true. A36 should not replace A572 in structural designs that require higher strength. Always check engineering specifications before making substitutions.
How to Specify Steel Correctly
When ordering structural steel, always specify the ASTM grade (A36 or A572), shape (beam, plate, angle, etc.), size, length, and quantity. This ensures you receive material that meets your project’s design requirements.
Which One Should You Choose?
Choose A36 if: Your project is light-duty, cost is the primary concern, you need maximum availability, or you are fabricating non-critical components.
Choose A572 if: Strength matters, you want to reduce total steel weight, you are building structural frames, or engineering efficiency is important.
Need A36 or A572 Steel? Tampa Steel & Supply Can Help
Whether you need A36 plate for fabrication or A572 beams for a structural project, Tampa Steel & Supply can help you confirm grade availability, pricing, and lead times. Our team works with builders, fabricators, and contractors across Florida every day.
Request a Quote Online or Call Tampa Steel & Supply at (813) 241-2801.