A36 vs A572 Grade 50 vs A992 — Compared
The three specifications that cover almost every rolled shape on a North American job. A36 is the old carbon default, A572 Grade 50 the general-purpose 50 ksi High-Strength Low-Alloy (HSLA) grade, and A992 the modern W-shape standard.
Side by side
| ASTM A36 | ASTM A572 Gr 50 | ASTM A992 | |
|---|---|---|---|
| Specification | ASTM A36 / A36M | ASTM A572 / A572M | ASTM A992 / A992M |
| Title | Carbon Structural Steel | High-Strength Low-Alloy Columbium-Vanadium Structural Steel | Structural Steel Shapes |
| Yield strength Fy (ksi) | 32–36 | 50 | 50 |
| Tensile strength Fu (ksi) | 58–80 | 65 | 65 |
| Fy/Fu ratio | n/a (Fu is a range) | grade-dependent | ≤ 0.85 |
| Applicable members | M, S, C, MC, L, MT, ST, plates, bars | W, M, S, HP, C, MC, L, WT, MT, ST, plates, bars | W (preferred), WT (preferred), HP, L, C, MC, M, S, MT, ST |
| Weathering | None. Requires coating in exposed or corrosive service. | None. See A588 for weathering HSLA. | None. |
| Welding | Excellent weldability, all common processes, typically no preheat for thin sections. | Weldable; heavier sections and higher grades may warrant preheat and procedure review. | Designed for weldability; capped carbon equivalent supports common processes. |
| Typical applications | Angles, channels, bracing, connections, embeds, base plates, miscellaneous steel. | HP bearing piles, high-strength plate girders, gusset and connection plates, transmission structures. | Building framing beams and columns, the standard for W-shape construction. |
| Availability | Very good for M, S, C, MC, L, plate, and bar. Limited for W (A992 has displaced it). | Grade 50 widely available. Grade 60/65 limited; confirm shape group and thickness before specifying. | Excellent, most economical W-shape spec. Domestic and import stock. |
Material constants
- Modulus of elasticity E: 29,000 ksi
- Shear modulus G: 11,200 ksi
- Density: 490 lb/ft³ (0.284 lb/in³)
- Poisson's ratio: 0.30
- Thermal expansion: 6.5 × 10⁻⁶ in/in/°F
These are the same for every structural steel grade. Strength changes with the specification; stiffness does not.
Related
- ASTM A36 / A36M Reference
strengths, applicable members and uses for ASTM A36 / A36M
- ASTM A572 Grade 50 Reference
strengths, applicable members and uses for ASTM A572 Grade 50
- ASTM A992 / A992M Reference
strengths, applicable members and uses for ASTM A992 / A992M
- ASTM Structural Steel Grades Reference
chemistry, tolerances and the full specification for every grade
- Steel Shape Properties Table
search and compare W, HP, S, M, C, MC, L, WT, HSS and pipe sections
The full specification
Chemistry, tolerances, coatings, galvanizing, weldability, availability and substitutions for every spec: ASTM 101 (STL+).