Industrial Fastener · Bolts Series
Heavy Hex Structural Bolt (A325 / A490)
Heavy hex structural bolts to ASTM A325 and A490 are the bolts that hold up structural steel buildings and bridges. They are high-strength, short-thread, heavy-hex-head bolts intended for use in pretensioned and slip-critical bolted connections. HDBolt sources A325/A490 sets — bolt + matching...
Product Overview
Heavy Hex Structural Bolt (A325 / A490) sourcing essentials
Heavy hex structural bolts to ASTM A325 and A490 are the bolts that hold up structural steel buildings and bridges. They are high-strength, short-thread, heavy-hex-head bolts intended for use in pretensioned and slip-critical bolted connections. HDBolt sources A325/A490 sets — bolt + matching A563 nut + F436 washer — from Yongnian factories that specialize in structural fasteners with traceable Mill Test Certificates.
ASTM A325 (Type 1, Type 3), ASTM A490 (Type 1, Type 3)
Material per requirement
Steel building frames, bridges, transmission towers, heavy machinery bases
Inspection records, lot labels, certificate options, and destination-ready packing.
Technical Data
Specification range
Final dimensions, mechanical properties, finish, and packing are confirmed against the RFQ and applicable standard.
| Standards | ASTM A325 (Type 1, Type 3), ASTM A490 (Type 1, Type 3) |
|---|---|
| Diameter Range | 1/2" – 1-1/2" (A325); 1/2" – 1-1/2" (A490) |
| Mating Components | A563 DH heavy hex nuts, F436 hardened structural washers |
| Surface Finish | Plain (A325/A490 Type 1), HDG (A325 Type 1 only), Weathering steel (Type 3) |
| Documentation | Mill Test Certificate (3.1) per heat lot, head markings per ASTM |
| Application | Steel building frames, bridges, transmission towers, heavy machinery bases |
Common surface finishes
Select an option to review its sourcing note. Exact coating system, thickness, and corrosion requirement are confirmed with the order.
Quality Control
Checked before consolidation and export
Each order is matched to the specified standard and verified at practical control points before shipment.
RFQ confirmation
Standard, size, grade, pitch, finish, certificates, packing, and destination are locked before production.
Lot verification
Critical dimensions, thread fit, markings, finish appearance, and packing labels are sampled and recorded.
Shipment approval
Photos and required reports are organized before consolidated loading and export documentation.
Buyer Questions
Frequently asked questions
What is the difference between A325 and A490 structural bolts?
A325 bolts have a minimum tensile strength of 120 ksi (for diameters up to 1"); A490 bolts have a minimum tensile strength of 150 ksi. A490 is used in connections where higher bolt pretension is required to achieve slip-critical capacity within practical bolt counts. A490 cannot be hot-dip galvanized due to hydrogen embrittlement risk.
Can A325 bolts be hot-dip galvanized?
Yes — A325 Type 1 bolts can be hot-dip galvanized after heat treatment, with appropriate baking to prevent hydrogen embrittlement. Galvanized A325 nuts (A563 DH) and washers (F436) are typically tapped or sized over to accommodate the zinc thickness. A490 bolts cannot be galvanized.
Are matching nuts and washers included?
Yes — when ordering structural bolts, we supply complete sets: A325/A490 heavy hex bolts + A563 DH heavy hex nuts + F436 hardened structural washers, all from the same shipment with matched MTCs. This is the standard structural fastener supply convention.
Ready to quote Heavy Hex Structural Bolt (A325 / A490)?
Send the standard, size, grade, finish, quantity, packing requirement, and destination. Availability and lead time are confirmed with the inquiry.