Structural Bolts

Heavy hex structural bolts for steel-to-steel connections in buildings, bridges, towers and solar structures: ASTM A325 / F3125 Grade A325, ASTM A490, DIN 6914 (HV system) and tension control (twist-off) bolts. They are supplied as matched sets with heavy hex nuts (ASTM A563 DH / A194 2H, DIN 6915) and hardened washers (ASTM F436, DIN 6916), with lot traceability and material certificates. Typical finishes are hot-dip galvanized, zinc flake or plain/black; electroplating is not used on A490 and class 10.9 structural bolts because of hydrogen embrittlement risk.

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Structural Bolts we supply

DIN 6914 HV Structural Bolt (EN 14399-4)

ASTM A490 Heavy Hex Structural Bolt

Tension Control (TC) Bolt — ASTM F3125 F1852 / F2280

ASTM A325 Heavy Hex Structural Bolt

Structural Bolts: standards, sizes and options
Product / standard	Sizes	Grades	Material	Finishes	MOQ
DIN 6914 / EN 14399-4 DIN 6914 HV Bolt	M12 – M36	10.9	Alloy steel, quenched and tempered	Hot-dip galvanized, Zinc flake (Dacromet/Geomet type), Plain	500 pcs / size
ASTM A490 / ASTM F3125 ASTM A490 Bolt	1/2" – 1-1/2"	A490 Type 1	Alloy steel, quenched and tempered	Plain, Zinc flake (Dacromet/Geomet type), Black oxide / phosphate	500 pcs / size
ASTM F3125 F1852 / ASTM F3125 F2280 Tension Control Bolt	M16 – M24; 5/8" – 1-1/8"	F1852 (A325 level), F2280 (A490 level), S10T	Alloy steel	Plain, Zinc flake (Dacromet/Geomet type), Mechanically galvanized	500 pcs / size
ASTM A325 / ASTM F3125 ASTM A325 Bolt	1/2" – 1-1/2"; M12 – M36	A325 Type 1	Medium carbon steel, quenched and tempered	Hot-dip galvanized, Zinc flake (Dacromet/Geomet type), Mechanically galvanized, Plain	500 pcs / size

Ordering structural bolts

MOQ: 500 pcs per size (negotiable for trial orders)
Mixed sizes: Welcome in one order
Samples: Samples available — cost and lead time quoted per request
Lead time: 15–25 days for standard parts; finishes such as HDG or Dacromet add a few days
Payment: T/T 30% deposit, 70% before shipment
Shipping: FOB Ningbo / CIF / DDP on request
Packaging: Cartons on pallets, or private-label boxes and bags
Documents: Material certificate, coating thickness and salt-spray reports on request
Custom: Drawings, non-standard sizes, coatings, marking and private-label packaging

To quote quickly, please send

Standard (e.g. DIN, ISO, ASTM) or drawing number
Size × length and thread pitch
Property class / grade and material
Finish and coating thickness (or the salt-spray hours you need)
Quantity per size and annual volume
Packaging and destination port

Finishes for structural bolts

Zinc-nickel and zinc are plated on our own line in Ningbo. Other finishes are applied by specialist coaters to the relevant standard.

Finish	Applied	Notes
Hot-dip galvanized	Available	ISO 10684 / ASTM F2329; nuts tapped oversize to suit
Zinc flake (Dacromet/Geomet type)	Available	Electrolyte-free, no hydrogen embrittlement risk
Plain	Available	For customer-side coating
Black oxide / phosphate	Available	Indoor or oiled service
Mechanically galvanized	Available	ASTM B695, common for high-strength parts

For property class 10.9 and above, choose zinc flake, or zinc-nickel with hydrogen-embrittlement relief agreed at order stage.

Row of zinc-nickel electroplating tanks — Our zinc-nickel plating line. Salt spray: 12 µm ≈ 1,000 h, 15 µm ≈ 1,440 h (neutral salt spray to first red rust). How zinc-nickel compares

How to choose

A325 or A490?: A490 has higher strength but must not be hot-dip galvanized or electroplated. A325 can be galvanized and covers most building connections.
Do I need a full bolting assembly?: Pre-loaded joints should use bolt, nut and washer from one manufacturing lot. We pack them as sets for that reason.

Request a structural bolt quote

Send sizes and quantities — we reply with price, finish options and lead time within 24 hours.