Studs
Studs are threaded rods, threaded both ends or fully, used where a bolt head won't fit or where frequent disassembly would damage a tapped hole. Stud bolts with nuts are standard for pipe flanges, engines, turbines and pressure equipment.
What it is
Double-ended studs screw into a tapped hole on one end and take a nut on the other; fully threaded stud bolts take nuts on both ends, typical in flange joints to ASME B16.5 with ASTM A193 B7 material and A194 2H nuts.
Studs are cut from threaded rod or machined, and threads are often rolled for strength.
Typical applications
- Pipe flange bolting
- Engine and cylinder head studs
- Pressure vessel and valve bolting
- Turbine and pump casings
- Machine assembly
Materials & grades
- Alloy steel ASTM A193 B7, B16
- Stainless B8 / B8M
- Carbon steel 8.8, 10.9
- Duplex and nickel alloys
Points to consider
- Specify material, thread, length and nut grade together.
- PTFE-coated studs resist corrosion and ease disassembly.
- Low-temperature service may need A320 L7 material.
- Tap-end studs need thread class matched to the tapped hole.
Frequently asked questions
What is a B7 stud bolt?
A stud bolt in ASTM A193 Grade B7 chromium-molybdenum alloy steel, standard for flange bolting.
Why use studs instead of bolts?
Studs protect tapped holes during repeated assembly and allow even clamping on flanges and casings.
What nuts go with B7 studs?
Typically ASTM A194 Grade 2H heavy hex nuts, which are rated to match B7 studs in pressure and temperature service.