ASTM A1085 Gr A — Yield Strength, Tensile Strength and Applications
ASTM A1085 Grade A: Fy 50 ksi, Fu 65 ksi (specified minimums). Tighter-tolerance cold-formed Hollow Structural Section (HSS). Design wall equals the full nominal wall (no 0.93 reduction), so the same size carries more capacity. One grade, Fy 50 ksi for round and shaped sections, with Charpy V-Notch (CVN) toughness as a base requirement.
Strength
| Grade | Fy (ksi) | Fu (ksi) | Note |
|---|---|---|---|
| A | 50 | 65 | Fy 50 ksi (max 70); round and shaped alike. |
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
Efficient HSS columns and braces where the full-wall capacity trims member size; connection-sensitive HSS.
Field notes
- Full nominal design wall instead of the 0.93 × nominal basis used for A500 (about 7.5% more design wall at the same nominal size; capacity gains vary by limit state).
- Fy = 50 ksi for round and shaped alike (A500 splits 46/50).
- CVN 25 ft-lbf at 40°F is a standard requirement; supplementary requirements apply when a more stringent toughness is specified.
- Credit full-wall capacity only if the material is ordered and certified to A1085.
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+).