2HMMatching nuts
ASTM A194 Grade 2HM
The sour service version of 2H, capped at 22 HRC. It is the nut for B7M studs — and the certificate must show the actual hardness reading, not just a pass mark.
- Base material
- Medium carbon steel
- Heat treatment condition
- Quenched and tempered, hardness-controlled
- Hardness, max
- 159–237 HBW, 22 HRC maximum
Service temperature
-48 °C+427 °C−273+900 °C
Required by NACE MR0175 / ISO 15156 wherever wet H₂S is present.
Chemical composition
| Element | Min (% by weight) | Max (% by weight) |
|---|---|---|
| C | 0.40 | — |
| Mn | 0.40 | — |
| P | — | 0.048 |
| S | — | 0.058 |
| Si | 0.10 | — |
Mechanical properties
ASTM A194 does not set a separate tensile requirement for nuts. The grade is controlled by hardness and by a proof load test, which is why the strength columns below read as dashes.
| Diameter | Tensile strength, min | Yield strength, min | Elongation, min | Hardness, max |
|---|---|---|---|---|
| Tat ca / All | — | — | — | 159–237 HBW · max 22 HRC |
Recommended coatings
Equivalent grades
- ASME SA194 2HM
- NACE MR0175 compliant nut
Need a quotation?
Send us the grade, size and quantity. We reply within one working day with price, lead time and the certificate package included.