ASTM F3125 Grade A490 bolts are premium, quenched-and-tempered alloy steel fasteners engineered exclusively for high-load moment frames, heavy crane runways, seismic structural joints, and critical load-transfer connections. Delivering a mandatory minimum tensile strength of 150 ksi (1,035 MPa), these fasteners provide maximum clamping force without increasing the bolt diameter, allowing engineers to design lighter, more efficient steel nodes.
Key Technical Features
150 ksi Heavy-Duty Performance
Developed for high-tier structural engineering where standard carbon steel fasteners fail to meet required yield safety margins.
Uniform Core Metallurgy
Continuous atmosphere-controlled heat treatment guarantees consistent tensile and yield values across the entire length, eliminating weak fracture zones in the thread roots.
AISC-Compliant Heavy Hex Head
Features an expanded structural hex head that maximizes tool engagement for calibrated wrenches or the turn-of-nut method, ensuring even distribution of massive pre-tension forces.
Strict Hydrogen Embrittlement Defense
Supplied exclusively in a plain, black-oxide lubricated finish. For environments requiring corrosion protection, we offer certified Grade A490 Type 3 Weathering Steel or approved zinc-flake alternatives.
Specifications
|
Item |
Specification |
|
Product Name |
A490 Bolts / ASTM A490 Structural Bolts |
|
Current ASTM Designation |
ASTM F3125 Grade A490 |
|
Material |
Quenched-and-tempered alloy steel |
|
Minimum Tensile Strength |
150 ksi (1,035 MPa) |
|
Minimum Yield Strength |
130 ksi for 1/2″–1″; 120 ksi for sizes above 1″ |
|
Head Type |
Heavy hex structural head |
|
Thread |
Unified National Coarse, Class 2A |
|
Size Range |
1/2″ to 1-1/2″ |
|
Standard Finish |
Plain, dark finish |
|
Installation |
Calibrated wrench or approved turn-of-nut method |
|
Application |
Pretensioned structural steel connections |
Applications
High-Rise Steel Frames
A490 structural bolts are used in heavily loaded beam-to-column joints, column splices, transfer structures, and moment-resisting frames. Their higher strength can support demanding connection designs while keeping the joint layout within practical dimensional limits.
Crane Runways and Heavy Lifting Structures
Crane runway beams and hoist-supporting steel experience repeated loading, vibration, and load reversal. A490 bolts are suitable for projects where the connection design requires high pretension and strict control of bolt installation.
Industrial Plants and Equipment Supports
Steel mills, power plants, processing facilities, and large equipment platforms often contain concentrated loads at base plates, support frames, and braced connections. The high-strength alloy-steel grade suits structural joints exposed to substantial static or dynamic forces.
Bridges and Long-Span Steelwork
Bridge members, long-span trusses, and heavily loaded steel assemblies require controlled load transfer at bolted joints. A490 bolts can be specified where the engineer requires the grade's higher mechanical capacity and the project conditions allow a plain or otherwise approved finish.
FAQ
Q: Can we order galvanized A490 bolts for outdoor infrastructure?
A: No. Due to the fact that hydrogen gas is easily absorbed during the chemical pickling process, traditional hot-dip galvanizing is limited. For outdoor structures that require this specific load characteristic, you need to choose our ASTM F3125 A490 type 3 weathering steel. This steel can form a self-protective anti-corrosion and oxidation layer.
Q: What is the difference between conventional A490 bolts and F2280 assemblies?
A: Conventional A490 bolts feature a standard heavy hex head installed via impact wrenches. F2280 assemblies are twist-off tension control (TC) bolts featuring a splined tail, requiring specialized electric shear wrenches to break off the tip once precise tension is achieved. We manufacture both variations with full Mill Test Reports (MTRs).
Q: Are A490 bolts interchangeable with A325 bolts?
A: No. A490 and A325 have different mechanical requirements and should not be substituted without approval from the design engineer. The connection design, pretension level, joint geometry, and finish restrictions must all be reviewed before changing grades.
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