A572 Grade 50 is a common, high-strength, low-alloy (HSLA) structural steel with a minimum yield strength of 50 ksi (50,000 psi), known for its excellent strength-to-weight ratio, making it ideal for bridges, heavy construction, truck frames, and poles, as it provides significant strength in lighter profiles compared to standard A36 steel. It's readily weldable and formable, often replacing older grades, and is used in beams, channels, angles, and plates for demanding applications.
Key Properties
Yield Strength: Minimum 50 ksi (50,000 psi)
Tensile Strength: Minimum 65 ksi (65,000 psi)
Type: High-Strength Low-Alloy (HSLA) Columbium-Vanadium Steel
Weldability:
Good, similar to A36 steel
What is the equivalent of A572 Grade 50 in European standards?
The closest European equivalent to ASTM A572 Grade 50 is S355J2 (+N) according to EN 10025-2:2019, though the precise match depends on the required sub-grade for impact toughness and the product form.
Here is a detailed breakdown of the equivalency:
Direct Comparison: A572 Grade 50 vs. S355J2
| Property | A572 Grade 50 (ASTM A572) | European Equivalent: S355J2 (EN 10025-2) |
|---|---|---|
| Minimum Yield Strength (ReH) | 50 ksi (345 MPa) | 355 MPa (for thicknesses ≤ 16mm)* |
| Tensile Strength (Rm) | 65 ksi min (450 MPa min) | 470 - 630 MPa |
| Material Type | High-Strength Low-Alloy (HSLA) | Non-alloy quality structural steel |
| Delivery Condition | Typically as-rolled (normalized optional) | Normalized (+N) or as-rolled |
| Key Distinction | Defined by mechanical properties; chemistry is flexible. | Defined by both mechanical properties and mandatory impact toughness. |
*Note on Yield Strength by Thickness: Both grades have de-rated yield strength for thicker sections. For example, S355J2 has a 355 MPa yield for ≤16mm, but drops to 335 MPa for >16-40mm, and 315 MPa for >40-63mm. Always verify the strength for the specific product thickness.
Selecting the Correct European "S355" Sub-Grade
The "J2" designation is critical. European S355 steels are subdivided by their impact toughness (Charpy V-notch) test temperature:
S355J2: Tested at -20°C. This is the most common and direct match for general structural use.
S355J0: Tested at 0°C. Used for less demanding ambient applications.
S355J2 (+N): The "+N" signifies normalized delivery, which is often the best match for the microstructural condition of A572 Grade 50. It is highly recommended for plates.
S355K2: Tested at -20°C with higher impact energy requirements than J2. Used for more critical applications.
S355N / NL: For thicker normalized plates with improved toughness at lower temperatures (-20°C or -50°C), per EN 10025-3.
Important Considerations for Substitution
Not a 1:1 Replacement: The standards systems (ASTM vs. EN) are different. Substitution requires formal approval under the governing design code (e.g., Eurocode 3 vs. AISC).
Product Form Matters: The equivalent may be specified under different product standards:
For Structural Sections: EN 10210-1 (S355J2H) for hot-finished hollow sections or profiles.
For Plates: EN 10025-2 is primary.
Welding Compatibility: While both weld well, filler metal selection must follow the European system (e.g., EN ISO 14341-A).
Practical Recommendation
When searching for a European equivalent to A572 Grade 50:
For general structural plates and sections, specify S355J2 (+N).
For applications requiring verified low-temperature toughness, specify S355N or S355NL.
Always confirm the yield strength for your specific product thickness and consult the EN standard to ensure all required properties (especially impact toughness) are met.
In summary, the primary and most widely accepted equivalent is S355J2 (+N), with careful attention to the sub-grade and thickness-dependent strength properties.
1. What is A572 Grade 50 steel used for?
A572 Grade 50 is commonly used in structural applications like building frames, bridges, transmission towers, and construction equipment where higher strength than A36 steel is needed.
2. What is the yield strength of A572 Grade 50?
The minimum yield strength of A572 Grade 50 is 50 ksi (345 MPa).
3. What is the difference between A572 Grade 50 and A36?
The main difference is strength: A572 Grade 50 has a higher yield strength (50 ksi vs. 36 ksi) and is a high-strength low-alloy (HSLA) steel, while A36 is a mild carbon steel.
4. Can A572 Grade 50 be welded?
Yes, it has good weldability using common methods like shielded metal arc welding (SMAW) and gas metal arc welding (GMAW), though proper procedures should be followed.
5. What is the chemical composition of A572 Grade 50?
It typically contains elements like carbon (max 0.23%), manganese (max 1.35%), phosphorus, sulfur, and may include small amounts of columbium, vanadium, or nitrogen for strengthening.
6. Is A572 Grade 50 corrosion resistant?
No, it is not a corrosion-resistant grade. For outdoor or corrosive environments, it usually requires protective coatings like paint or galvanizing.
7. What are the available forms of A572 Grade 50?
It is widely available in structural shapes (beams, channels, angles), plates, bars, and sheets.
8. What is the equivalent of A572 Grade 50 in European standards?
The closest European equivalent is S355JR or S355J2 according to EN 10025-2, though exact matching depends on thickness and impact requirements.
9. How does A572 Grade 50 compare to A992 steel?
A992 is a newer, more tightly controlled structural steel primarily for wide-flange shapes, with similar yield strength (50-65 ksi) but stricter chemical and mechanical limits.
10. What is the price of A572 Grade 50 compared to A36?
A572 Grade 50 typically costs 10-25% more than A36 due to its higher strength and alloy content, but prices vary with market conditions and order size.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
