The heavy hex nut that mates with B7 studs and A325 bolts — the “2H” you see stamped on a flange nut.
ASTM A194 Grade 2H is a quenched-and-tempered carbon-steel heavy hex nut built for heat and pressure service. It’s the standard nut for B7 studs on flanges and a common mate for A325 structural bolts — strong enough to develop the bolt’s full strength.
Heavy hex nuts (heat / pressure)
“2H” stamped on a face
With B7 studs & A325 bolts
| Property | Detail |
|---|---|
| Material | Carbon steel, quenched & tempered |
| Hardness | 24–38 HRC |
| Style | Heavy hex |
| Marking | “2H” + manufacturer |
You’ll find 2H nuts on flanged joints (two per B7 stud) and on A325 structural connections — anywhere the nut has to keep up with a high-strength bolt or stud under temperature and load. Pairing matters: a softer nut would strip before the stud reached its rating. See the nut compatibility chart.
Stamped “2H” on one face, in the heavy hex pattern. If you’ve got B7 studs, the 2H nut is almost always the right partner — two per stud, one on each end.
A194 2H nuts to match your B7 studs and A325 bolts — the right count, every time. Tell us the stud size and quantity.
