ASTM A572 Grade 50 High-Strength Low-Alloy Steel
ASTM A572/A572M · Published: 2026-05-23 · Updated: 2026-07-07
ASTM A572 Grade 50 is a high-strength low-alloy (HSLA) structural steel with columbium-vanadium micro-alloying that delivers 345 MPa minimum yield strength—38% stronger than A36. Its superior strength-to-weight ratio allows engineers to reduce...
ASTM A572 Grade 50 is a high-strength low-alloy (HSLA) structural steel with columbium-vanadium micro-alloying that delivers 345 MPa minimum yield strength—38% stronger than A36. Its superior strength-to-weight ratio allows engineers to reduce structural weight by 20-30% compared to A36 designs. Commonly used for bridges, transmission towers, construction equipment, and heavy-duty structural applications. Available in plates, shapes, and sheet piling with good weldability using low-hydrogen practices.
Quick Facts
| Category | Carbon Steel |
| Standard | ASTM A572/A572M |
| Density | 7.85 g/cm³ |
| Yield Strength | 345 MPa (50 ksi) |
| Tensile Strength | 450 MPa (65 ksi) |
Global Equivalents & Cross-Reference
| Alternative Standard / Grade | Action |
|---|---|
| S355JR | Compare |
| Q355 | Compare |
| SM490 | Compare |
| St52-3 | Compare |
| E355 | Compare |
Heat Treatment & Processing
| Normalizing | 870-900°C, air cool |
| Stress Relieving | 595-650°C, 1h/25mm |
Welding & Fabrication
| Preheat | Not required <20mm |
| Filler Metal | E7018, ER70S-6 |
| Interpass Temp | Max 315°C |
| Weldability Rating | Excellent |
Related Materials
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Frequently Asked Questions
Can A572 Grade 50 replace A36 in structural design?
Yes, A572 Gr 50 can replace A36 in most structural applications with significant weight savings. The higher strength allows lighter sections, but designers must check deflection and stability limits which may govern with thinner sections. Welding procedures should use matching-strength filler metals (e.g., E70XX electrodes).
References & International Standards
- ASTM International. Standard Specifications for Steel & Metal Alloys. astm.org
- International Organization for Standardization (ISO). Metallic Materials — Cross-Reference Database. iso.org
- American Iron and Steel Institute (AISI). Steel Grade Designations & Equivalents. steel.org
- European Committee for Standardization (CEN). EN Steel Standards & Numbering System. cencenelec.eu