A572 Grade 50 Steel properties
A572 Grade 50 is a high-strength low-alloy (HSLA) structural steel. Small alloy additions give it a 50 ksi yield, far above plain A36, at nearly the same weight, so it is widely used to build lighter, stronger structures.
Mechanical properties
| Property | Value |
|---|---|
| Yield strength | 50 ksi (345 MPa) |
| Ultimate tensile strength | 65 ksi (450 MPa) |
| Elongation | 18% |
| Hardness | about 150 HB (Brinell) |
| Modulus of elasticity | 29,000 ksi (200 GPa) |
Physical properties
| Property | Value |
|---|---|
| Density | 0.284 lb/in³ (7850 kg/m³) |
| Melting point | about 1425 to 1540 °C |
Thermal properties
| Property | Value |
|---|---|
| Thermal conductivity | about 50 W/m·K |
| Thermal expansion | 11.7 µm/m·°C |
| Specific heat | 486 J/kg·K |
Values are typical for the grade and condition shown. Actual properties vary with temper, heat treatment, and product form, so use these for comparison and preliminary design and confirm against material certificates for final work.
Compare with other materials
See the Material Properties Comparison, Yield Strength, and Density charts.
Typical uses
A572-50 is used for buildings, bridges, transmission towers, and heavy equipment frames where strength-to-weight matters. Its higher yield lets designers use thinner, lighter sections than A36 for the same load, cutting weight and cost in large structures.
How it compares
A572-50 delivers about 40 percent more yield strength than A36 at the same density, while keeping good weldability. It is the most common HSLA structural grade, chosen whenever the weight savings over A36 justify the modest cost premium.
FAQ
What is the difference between A36 and A572-50?
A572-50 has a 50 ksi yield versus A36 at 36 ksi, so it carries more load per pound. Both weld well; A572 lets you use lighter sections.
Is A572 Grade 50 weldable?
Yes. It is designed as a weldable structural steel and is used extensively in welded buildings and bridges.
What does HSLA mean?
High-strength low-alloy. Small alloy additions raise the strength well above plain carbon steel without much added weight or cost.