ASME · ANSI / ASME B18.31.2

ASME B18.31.2 Standard: Technical Requirements for Inch Studs and Flange Fasteners

Technical specification and purpose of the ASME B18.31.2 standard

This standard regulates the geometric parameters, tolerances, and design features of inch-series fasteners. The EV Group China technological regulation relies on these specifications for the production and supply of the following types of hardware:

• Continuous thread studs (fully threaded).
• Double-end studs (stud bolts).
• Fasteners for flange connections.

The engineering department of EV Group China identifies the following design configurations described in the standard:

Continuous thread stud: a fastener with a uniform thread profile along the entire length of the rod, ensuring even load distribution during tightening.

Double-end stud (symmetrical): a product with identical thread parameters on both ends, optimized for fastening two mating parts using two nuts. It is used in critical assemblies with high alignment requirements.

Double-end stud (asymmetrical): structurally designed for screwing into the body of one of the parts (threaded hole). The geometry of the ends varies depending on project requirements, ensuring reliable fixation in equipment blocks.

The EV Group China product range includes studs that comply with the standard, featuring the following rod types:

• Rod with a reduced diameter to improve fatigue strength.
• Full-diameter rod. Flange studs intended for use in connections according to the ASME B16.5 standard are manufactured using high-strength steels according to ASTM A193/A193M (including B7, B8, and B8M series grades).

EV Group China specialists emphasize: the presence of a specific item in the standard does not guarantee stock availability of the entire size range. To optimize deliveries and select analogs for project specifications, we recommend sending a request to the technical department of EV Group China.