SPECIFICATION LIBRARY

ASTM F3125

ASTM F3125: A Structural Powerhouse

Note: The specifications for A325 and A490 were integrated into the ASTM F3125 specification in 2016. This consolidation was part of an effort to streamline and simplify the standards for high-strength structural bolts, making it easier for industry professionals to specify and select fasteners for construction and engineering projects.

ASTM F3125 is a comprehensive specification that covers high-strength structural bolts, incorporating several grades previously covered under separate standards. This specification lays out the requirements for structural bolting applications, focusing on grades A325, A325M, F1852, A490, A490M, and F2280, which are widely used in the construction of steel structures and bridges.

Grade Classifications of ASTM F3125

Grade

Description

Tensile Strength

Common Applications

A325

Carbon steel bolts and studs

120 ksi min

Structural steel connections in buildings, bridges

A325M

Metric version of A325

830 MPa min

Similar to A325, for use in metric standards

F1852

Twist-off type tension-control bolt assemblies

Corresponds to A325

Used where controlled tensioning is needed

A490

Alloy steel bolts, higher strength than A325

150 ksi min

High-stress structural applications

A490M

Metric version of A490

1040 MPa min

Similar to A490, for use in metric standards

F2280

Twist-off type tension-control bolt assemblies, high strength

Corresponds to A490

High-stress applications requiring controlled tensioning

Chemical Composition

The ASTM F3125 specification defines the chemical composition of its grades to ensure the bolts achieve the necessary mechanical properties:

Grade

Carbon

Manganese

Phosphorus

Sulfur

Silicon

Alloy Elements

A325

0.30-0.52%

0.60% min

≤ 0.035%

≤ 0.040%

A325M

0.30-0.52%

0.60% min

≤ 0.035%

≤ 0.040%

A490

0.15-0.35%

0.50-0.90%

≤ 0.035%

≤ 0.040%

Chromium, Nickel, Molybdenum

A490M

0.15-0.35%

0.50-0.90%

≤ 0.035%

≤ 0.040%

Chromium, Nickel, Molybdenum

F1852

Corresponding to A325

F2280

Corresponding to A490

Mechanical Properties

Grade

Tensile Strength

Yield Strength

Elongation

Hardness

A325

120 ksi min

92 ksi min

14% min

248-327 HB

A325M

830 MPa min

660 MPa min

14% min

248-327 HB

A490

150 ksi min

130 ksi min

14% min

277-363 HB

A490M

1040 MPa min

900 MPa min

14% min

277-363 HB

F1852

Corresponding to A325

F2280

Corresponding to A490

Applications and Usage

  • A325 and A325M bolts are primarily used in structural steel connections in heavy steel structures such as buildings, bridges, and highway structures.

  • F1852 bolts are used where tension control is crucial, allowing for easier and faster installation.

  • A490 and A490M bolts provide higher strength and are used in critical structural applications that demand high tensile loads.

  • F2280 bolts, like F1852, are designed for high-stress applications where controlled tensioning and ease of installation are beneficial.

Manufacturing Process and Quality Assurance

ASTM F3125 bolts undergo controlled heat treatment processes to achieve the desired mechanical properties. Manufacturers must adhere to strict quality control and testing protocols, including tensile testing, hardness testing, and rotational capacity testing, to ensure that the bolts meet the stringent requirements of the ASTM F3125 standard.

 

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