A500 Grade B vs Grade C — Compared
The two Hollow Structural Section (HSS) grades in common supply. Grade C buys 4 ksi of yield over Grade B at the same wall (46 vs 42 round, 50 vs 46 shaped), which is why most mills now stock it.
Side by side
| ASTM A500 Gr B | ASTM A500 Gr C | |
|---|---|---|
| Specification | ASTM A500 / A500M | ASTM A500 / A500M |
| Title | Cold-Formed Welded and Seamless Carbon Steel Structural Tubing (HSS) | Cold-Formed Welded and Seamless Carbon Steel Structural Tubing (HSS) |
| Yield strength Fy (ksi) | 42–46 | 46–50 |
| Tensile strength Fu (ksi) | 58 | 62 |
| Fy/Fu ratio | grade/shape-dependent | grade/shape-dependent |
| Applicable members | HSS Round, HSS Square, HSS Rectangular | HSS Round, HSS Square, HSS Rectangular |
| Weathering | None. See A847 for weathering HSS. | None. See A847 for weathering HSS. |
| Welding | Weldable; avoid welding in the cold-worked corner regions where ductility is reduced. | Weldable; avoid welding in the cold-worked corner regions where ductility is reduced. |
| Typical applications | Columns, braces, truss members, railings, architecturally exposed HSS, posts. | Columns, braces, truss members, railings, architecturally exposed HSS, posts. |
| Availability | Very good. Grade C is now standard mill production in the US. | Very good. Grade C is now standard mill production in the US. |
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 A500 Grade B Reference
strengths, applicable members and uses for ASTM A500 Grade B
- ASTM A500 Grade C Reference
strengths, applicable members and uses for ASTM A500 Grade C
- 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+).