Technical specifications and scope of ASTM F3148
This specification establishes strict requirements for the physical and mechanical properties, chemical composition, and geometric parameters of high-strength carbon and alloy steel bolts supplied in imperial units. EV Group China products compliant with the F3148 standard are complete fastener assemblies consisting of a bolt with a special splined end, a specialized nut, and at least one washer.
Engineering purpose
Fasteners in this category are intended for use in critical structural steel applications. Assembly is performed using “torque-to-turn” or combined methods that ensure controlled pretensioning force. The standard covers a range of bolts with nominal thread diameters from ½ to 1 ¼ inches.
Classification and marking
Structural elements are classified as Grade 144. The steel type selection is determined by service conditions and corrosion resistance requirements:
- Type 1 (144 ksi) — carbon, boron-containing, or alloy steels subjected to quenching and tempering.
- Type 3 (144 ksi) — weathering alloy steels suitable for service in aggressive environments without additional protective coatings.
The terminology used within this specification fully complies with the provisions of the ASTM F1789 standard. The splined bolt is a precision component featuring a shaft with vertical grooves at the end beyond the threaded section, providing a secure grip for installation tools.
Installation technology
EV Group China kits are optimized for automated assembly using specialized electric torque tools. During tightening, the tool’s inner socket grips the splined shaft to prevent rotation, while the outer socket rotates the nut. Two-stage control (torque application followed by a specified rotation angle) ensures the achievement of design connection characteristics.