A325 Structural Bolts Suppliers
36 vetted U.S. suppliers · 23 states
ASTM A325 (now F3125 Grade A325) structural bolts are the high-strength fasteners for bolted steel connections — beams, columns, baseplates, and any structural-erection work. Below is our live count of vetted U.S. suppliers with state distribution and a one-click RFQ flow.
Geographic distribution
Where these suppliers are
Top 8 states by vetted-supplier density. 15 more across 15 additional states — listed below the chart.
Also covered
Minnesota (1) · Missouri (1) · Pennsylvania (1) · Colorado (1) · Kansas (1) · Ohio (1) · Kentucky (1) · Mississippi (1) · Louisiana (1) · North Carolina (1) · Florida (1) · Wisconsin (1) · Nebraska (1) · Alabama (1) · Indiana (1)
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What A325 structural bolts are
A325 (now covered under ASTM F3125 Grade A325) is the high-strength carbon-steel structural bolt for shear and tension connections in bolted steel construction. Minimum tensile strength: 120 ksi for ½–1", 105 ksi for >1" through 1½". Heads are heavy hex (larger than standard hex), with A325 markings on the head per AISC requirements. Common downstream: structural-steel connection bolts per AISC 360, plate girders, moment connections, and any bolted steel-erection work.
What to look for in a supplier
Confirm the supplier ships to current F3125 Grade A325 spec — the older A325 spec was withdrawn in 2016 and replaced by F3125. Ask about marking (A325 head stamp), heat lot traceability, and whether bolts ship with matching nuts (A563 Grade DH or A194 2H) and washers (F436). Decide on finish: black (as-quenched) is cheapest; mechanically galvanized and hot-dip galvanized are options for corrosion. Confirm the supplier ships standard kits (bolt + nut + washer) or component-only — most structural work specifies kits. Be explicit about the test method requirement: turn-of-nut, calibrated wrench, or direct tension indicators all have spec implications.
FAQ
Common questions
What's the difference between A325 and A490?
Both are structural bolts. A325 = 120 ksi tensile, used for most general structural connections. A490 = 150 ksi tensile, used for higher-stress connections (large moment connections, heavy industrial). A490 is more expensive and has different installation requirements; substitute only with engineer approval.
Is A325 the same as F3125 Grade A325?
Yes — the A325 spec was withdrawn in 2016 and consolidated into F3125, which covers A325, A490, and metric equivalents in a single document. Most suppliers list these interchangeably. If your project spec calls out A325 by the old name, F3125 Grade A325 is the correct material.
Should A325 bolts ship in kits with nuts and washers?
Yes — for structural work the bolt, nut (A563 Grade DH), and washer (F436) all need to be matched and certified. Most fastener suppliers ship structural-bolt assemblies as kits; verify the kit components match the spec on the PO.
What's the difference between hot-dip galvanized and mechanical galvanized A325?
Hot-dip galvanized (HDG) is a thicker zinc coating (~3 mils minimum) — better corrosion protection but adds dimensional buildup that requires nut overtapping. Mechanically galvanized is thinner (~2 mils typical) — slightly less corrosion protection but better dimensional fit. Most structural specs accept either; confirm with the project engineer.
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