B7 Studs

B7 studs are high-strength threaded fasteners made from ASTM A193 Grade B7 chromium-molybdenum alloy steel, the industry standard for bolted flange connections in piping, pressure vessels, and high-temperature service. Heat-treated for strength and elevated-temperature performance, they're paired with matching 2H heavy hex nuts. We stock B7 studs fully threaded and tap-end across finishes.

What Makes B7

ASTM A193 B7 is a quenched-and-tempered chromium-molybdenum alloy (AISI 4140-type) rated to 125 ksi tensile, with reliable strength at elevated temperatures up to about 1000°F. This combination of strength and heat resistance is why B7 is specified for flanges, valves, and pressure equipment across oil, gas, and process industries.

Stud Configurations

Fully threaded (continuous thread): threaded end to end, the most common for flanges. Tap-end / double-end: threaded only at the ends with a plain center, for specific assembly needs. Both pair with ASTM A194 Grade 2H heavy hex nuts, the standard mating nut for B7.

Finishes

Plain (often light-oiled), zinc, hot-dip galvanized, and PTFE/fluoropolymer coatings (e.g., blue/Xylan) that resist corrosion and ease assembly and disassembly in process service. Coated studs are common where galling and seized flanges are concerns.

Dimensional Standards

B7 studs are manufactured to ASTM A193 Grade B7 for material and ASME B16.5 / B18.31.2 for flange stud dimensions, with A194 2H nuts.

Selecting the Right B7 Stud

Match length to the flange and gasket stack plus nut engagement, choose fully-threaded for standard flanges, and pair with 2H nuts. Select a coating (PTFE) for corrosive service and easier future disassembly. Confirm temperature and pressure ratings suit your application, and follow the proper bolt-tightening pattern and torque for flange sealing.

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