Features of ASTM A325 A490 Heavy Hex Bolt

Various lengths for choosing
Features a “heavy hex” head design that is larger and thicker than standard hex bolts
Offers higher load-bearing capacity and shear strength
Suitable for installation with larger torque, providing more reliable fastening effects.

Product Parameter (Specification)

Standard	DIN,ASTM/ANSI, JIS, EN, ISO, AS	Material	Medium carbon steel, Alloy steel
Surface Treatment	Zinc Plated, Hop Dip Galvanized(HDG) phosphorization, Black Oxide, Geomet,Dacroment, Nickel plated, Zinc-Nickel plated	Shank	Full thread, Half thread
Grade	ASTM A325 A490	Size	3/8’’-2-1/2’’, M12-M64
Unite	Piece	Packing	Bulk cartons with pallet, small boxes in cartons with pallet

Product Application

ASTM A325 A490 Heavy Hex Bolt is widely used in heavy Industry, mining, water treatment, healthcare, retail industry, general industry, Oil & Gas, automotive industry etc.

ASTM A325/A490 Heavy Hex Bolt Application Scenario Table

Application Scenario	Recommended Bolt Type	Key Considerations
Commercial & Industrial Steel Buildings: Beam-column joints, truss connections, and steel frame fixing in shopping malls, factories, and warehouse facilities.	ASTM A325	– Control torque coefficient per ASTM F2280 to ensure preload accuracy. – Use hot-dip galvanizing (HDG) for outdoor bolts to resist atmospheric corrosion. – Match with ASTM A563 Grade DH nuts for load-bearing consistency.
Heavy-Duty Highway/Railway Bridges: Main girder connections, pier steel structures, and orthotropic steel deck fastening in long-span bridges or coastal-crossing bridges.	ASTM A490	– Meet minimum tensile strength of 150 ksi (1034 MPa) as required by the standard. – Prioritize Type 3 weathering alloy steel for coastal bridges to reduce maintenance frequency. – Conduct wedge load tests per ASTM F1852 to verify structural integrity.
Heavy Machinery Manufacturing: Base fixing of mining excavators, hydraulic presses, and flange docking of large gearboxes/motors in heavy industrial equipment.	ASTM A490	– Pair with high-strength washers (ASTM F436) to distribute load and prevent surface damage. – Use hydraulic tensioners for preload instead of torque wrenches to avoid vibration-induced loosening. – Avoid over-tightening to prevent exceeding the bolt’s yield strength (120 ksi).
Marine & Corrosive Environments: Offshore platform auxiliary structures, port crane steel frames, and coastal power plant steel supports exposed to saltwater or high humidity.	ASTM A325 / ASTM A490	– Prohibit galvanization for A490 bolts to prevent hydrogen embrittlement. – Select bolts with phosphate + paint coating for enhanced corrosion resistance in high-salt areas. – Provide material certification (MTR) to confirm compliance with weathering steel composition.
Industrial Equipment & Pipelines: Boiler accessory fastening, high-pressure pipeline flanges (≤300℃) in chemical, petrochemical, or thermal power plants.	ASTM A325	– Verify heat stability of bolts for high-temperature applications (max 300℃ for A325). – Use thread lockers for pipeline flanges to resist fluid-induced vibration. – Inspect bolt tightness quarterly in cyclic temperature environments.

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ASTM F3125 Grade A325/A490 Heavy Hex Bolts

1. Medium carbon steel & Alloy steel
2. Highly corrosion-resistant surface treatment
3. Classified as high-strength bolts, manufactured in compliance with ASTM A325 and ASTM A490 standards
4. Designed for use with nuts

Category: Hex Bolt

Description

Standard	DIN,ASTM/ANSI, JIS, EN, ISO, AS	Material	Medium carbon steel, Alloy steel
Surface Treatment	Zinc Plated, Hop Dip Galvanized(HDG) phosphorization, Black Oxide, Geomet,Dacroment, Nickel plated, Zinc-Nickel plated	Shank	Full thread, Half thread
Grade	ASTM A325 A490	Size	3/8’’-2-1/2’’, M12-M64
Unite	Piece	Packing	Bulk cartons with pallet, small boxes in cartons with pallet

Application Scenario	Recommended Bolt Type	Key Considerations
Commercial & Industrial Steel Buildings: Beam-column joints, truss connections, and steel frame fixing in shopping malls, factories, and warehouse facilities.	ASTM A325	– Control torque coefficient per ASTM F2280 to ensure preload accuracy. – Use hot-dip galvanizing (HDG) for outdoor bolts to resist atmospheric corrosion. – Match with ASTM A563 Grade DH nuts for load-bearing consistency.
Heavy-Duty Highway/Railway Bridges: Main girder connections, pier steel structures, and orthotropic steel deck fastening in long-span bridges or coastal-crossing bridges.	ASTM A490	– Meet minimum tensile strength of 150 ksi (1034 MPa) as required by the standard. – Prioritize Type 3 weathering alloy steel for coastal bridges to reduce maintenance frequency. – Conduct wedge load tests per ASTM F1852 to verify structural integrity.
Heavy Machinery Manufacturing: Base fixing of mining excavators, hydraulic presses, and flange docking of large gearboxes/motors in heavy industrial equipment.	ASTM A490	– Pair with high-strength washers (ASTM F436) to distribute load and prevent surface damage. – Use hydraulic tensioners for preload instead of torque wrenches to avoid vibration-induced loosening. – Avoid over-tightening to prevent exceeding the bolt’s yield strength (120 ksi).
Marine & Corrosive Environments: Offshore platform auxiliary structures, port crane steel frames, and coastal power plant steel supports exposed to saltwater or high humidity.	ASTM A325 / ASTM A490	– Prohibit galvanization for A490 bolts to prevent hydrogen embrittlement. – Select bolts with phosphate + paint coating for enhanced corrosion resistance in high-salt areas. – Provide material certification (MTR) to confirm compliance with weathering steel composition.
Industrial Equipment & Pipelines: Boiler accessory fastening, high-pressure pipeline flanges (≤300℃) in chemical, petrochemical, or thermal power plants.	ASTM A325	– Verify heat stability of bolts for high-temperature applications (max 300℃ for A325). – Use thread lockers for pipeline flanges to resist fluid-induced vibration. – Inspect bolt tightness quarterly in cyclic temperature environments.

ASTM F3125 Grade A325/A490 Heavy Hex Bolts

ASTM A325/A490 Heavy Hex Bolt Application Scenario Table

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