A500 vs A1085

ASTM A1085/A1085M covers cold-formed welded carbon steel HSS for welded or bolted construction — buildings, bridges, towers, cranes, sign structures, offshore platforms, protective structures, and amusement rides. Relative to A500 it offers one grade with a defined yield range instead of four grades, tighter mass and wall-thickness provisions that let designers use the full nominal wall in design, a maximum yield limit useful for seismic capacity design, and an optional Charpy V-notch supplement for notch-toughness-critical work.

A1085 is welded-only and its scope starts at a heavier minimum wall (0.148 in. [3.8 mm]) than A500's, so light-wall product remains A500 territory.

The design-wall question is the headline: North American practice reduces A500's nominal wall for design because of its mass tolerance, while A1085's tighter provisions were written so the nominal wall can be used directly. For seismic systems, A1085's capped yield supports capacity-design assumptions that A500's open-ended grades complicate.

• A500: four grades, welded and seamless, broadest availability and size range
• A1085: single grade, welded only, tighter mass/wall provisions, optional CVN supplement
• A1085 typically carries a price and availability premium — confirm producer coverage early
• Dynamically loaded and fracture-critical work is where A1085's CVN option earns its cost

Stay with A500 for the broad run of building columns, braces, and frames where the design already uses the reduced-wall convention and stock availability matters. Consider A1085 for seismic force-resisting systems, bridge and dynamically loaded members, and projects where the full-nominal-wall design basis meaningfully reduces member sizes. The decision belongs in the design phase — retrofitting it at procurement rarely works.