ASTM A501 — Yield Strength, Tensile Strength and Applications
Hot-formed Hollow Structural Section (HSS) in round, square and rectangular shapes. Uniform properties around the section, no work-hardened corners. A501-21 covers Grades A, B and C.
Strength
| Grade | Fy (ksi) | Fu (ksi) | Note |
|---|---|---|---|
| A | 36 | 58 | — |
| B | 50 | 70 | — |
Fy and Fu are specification minimums. Verify the grade on the Mill Test Report (MTR); dual-certified material is common.
Applicable members
HSS Round, HSS Square, HSS Rectangular
Applicable is not the same as stocked. Confirm availability with the supplier.
Common applications
HSS members where hot-formed uniformity or toughness is preferred over cold-formed A500.
Field notes
- No work-hardened corners, so corner welding is less of a concern than A500.
- Availability: the Steel Tube Institute reports no domestic HSS producer rolling A501 for structural use. Most jobs default to A500.
- American Institute of Steel Construction (AISC) 360 B4.2 design rule: use design wall = 0.93 × nominal unless the provision permits otherwise.
- Grade C (added in A501-21) is not tabulated here; confirm its Fy, Fu and thickness limits against the current standard before specifying.
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 Structural Steel Grades Reference
chemistry, tolerances and the full specification behind this grade
- Steel Shape Properties Table
the sections this grade is supplied in
- Bolt Tensile & Shear Capacity Calculator
fastener grades to match this base metal
- Fillet Weld Strength Calculator
electrode selection to match this base metal
The full specification
Chemistry, tolerances, coatings, galvanizing, weldability, availability and substitutions for every spec: ASTM 101 (STL+).