ASTM A194 Grade 2H Equivalent Materials — Cross-Reference
ASTM A194 Grade 2H is a quenched-and-tempered medium-carbon steel heavy hex nut (UNS K04100). When 2H is not available, the following equivalent or near-equivalent grades are commonly substituted in industrial bolting applications.
Direct ASTM Equivalents
| Standard | Grade | UNS / Material | Notes |
|---|---|---|---|
| ASTM A563-DH | DH | Carbon Steel Q&T | Direct interchange for structural bolting; same Q&T treatment |
| ASTM A563M | 10S | Carbon Steel Q&T | Metric equivalent |
| ASTM A194 | 2HM | UNS K04100 | Sour-service variant (NACE MR0175 hardness-controlled) |
| ASTM A194 | 4 | UNS G41400 | Higher-strength Cr-Mo alloy alternative |
International Equivalents
| Region / Standard | Equivalent Grade | Notes |
|---|---|---|
| BS 6105 (UK) | Grade 5 | Q&T carbon steel hex nut |
| DIN 267-7 (Germany) | Grade 8 / 10 | Property class 8 or 10 metric hex nut |
| JIS B 1181 (Japan) | Class 8 / 10 | Japanese metric hex nut grade 8 or 10 |
| ISO 898-2 | Class 8 / 10 | International metric nut property class |
| EN ISO 4032 | Class 8 | European metric hex nut equivalent |
When NOT to Substitute
Grade 2H should not be substituted with commercial-grade hex nuts (ASTM A563-A, ASTM A307) for high-pressure/high-temperature service. The Q&T treatment in A194 Grade 2H is essential for the proof load and hardness specified for refinery, petrochemical, and pressure-vessel bolting up to 800°F.
Companion Stud Bolt Grades
ASTM A194 Grade 2H is the canonical nut for the following ASTM A193 stud bolt grades:
- A193 Grade B7: AISI 4140 Cr-Mo alloy — most common pairing for refinery flange bolting
- A193 Grade B16: Cr-Mo-V alloy — high-temperature service up to 1100°F
- A193 Grade B7M: sour-service Cr-Mo (paired with A194 Grade 2HM)
For more on A194 grades, see the A194 hub or download the A194 specification PDF.