ASTM A194 Grade 7 — Chemical Composition & Mechanical Properties
ASTM A194 Grade 7 is a bolting & nut grades grade for heavy hex nuts (UNS G41400, EN / W.Nr ≈ 1.7225). It is also known as AISI 4140. This sheet summarises its chemical composition limits, minimum mechanical properties, heat treatment and typical service. Teshi Group manufactures stud bolts and nuts in this grade.
ASTM A194 Grade 7 at a glance
| Specification | ASTM A194 Grade 7 |
|---|---|
| Material family | Bolting & nut grades |
| Product form | Heavy hex nuts |
| UNS number | G41400 |
| EN / W.Nr equivalent | ≈ 1.7225 |
| Also known as | AISI 4140 |
| Document | TG-MG-127 · Rev. 1 · October 2026 |
Typical service
Nuts for B16 and L7 bolting in high-temperature and low-temperature service
Heat treatment
Quenched and tempered 595 °C min
Chemical composition of ASTM A194 Grade 7 (weight %)
Single values are maximums unless shown as a range or “min”.
Mechanical properties
| Proof load stress | 1205 MPa (175 ksi), heavy hex |
|---|---|
| Hardness | 248–327 HBW (24–35 HRC) |
About bolting & nut grades
Flange bolting is specified as a stud-bolt grade plus a nut grade. ASTM A193 covers high-temperature bolting (B7, B7M, B16, B8, B8M), A320 covers low-temperature bolting (L7, L7M, L43, B8 classes), A453 covers high-strength austenitic bolting (Grade 660), and A194 covers the nuts (2H, 2HM, 4, 7, 8, 8M).
Reference information compiled from the published standard for convenience. It does not replace the current edition of the governing standard, which takes precedence. Verify critical dimensions and properties before design, purchase or fabrication. Teshi Engineers & Sales Promoters (P) Ltd accepts no liability for errors or omissions.
International equivalents of ASTM A194 Grade 7
All equivalents| Standard system | Nearest equivalent grade |
|---|---|
| USA — ASTM / ASME | ASTM A194 Grade 7 · ASME SA-194 Grade 7 |
| USA — UNS | G41400 |
| Europe — EN designation | 42CrMo4 |
| Europe — W.Nr | 1.7225 |
| Japan — JIS | SCM440 / SNB7 (JIS G4107) |
| China — GB / NB | 42CrMo (GB/T 3077) |
| China — old GB designation | 42CrMo |
| India — IS | 42Cr4Mo2 (IS 1570) |
| UK — BS (withdrawn) | BS 970 708M40 |
Equivalents are the nearest commonly cited grades. Chemistry, mechanical properties and testing differ between standards — compare them before substituting one for another.
Same alloy in other product forms
| Product form | Specification / grade |
|---|---|
| Stud bolts / bolting | ASTM A193 B7 |
| Stud bolts / bolting | ASTM A193 B7M |
| Stud bolts / bolting | ASTM A320 L7 |
| Stud bolts / bolting | ASTM A320 L7M |
FAQ
ASTM A194 Grade 7: common questions
What is the proof load stress of ASTM A194 Grade 7 nuts?
1205 MPa for heavy hex nuts.
What is the carbon content of ASTM A194 Grade 7?
0.37–0.49 %.
What is the UNS number and EN equivalent of ASTM A194 Grade 7?
UNS G41400; the nearest European designation is W.Nr ≈ 1.7225. Equivalents are close but not identical — check the specification if substituting.
How is ASTM A194 Grade 7 heat treated?
Quenched and tempered 595 °C min.
What is the Chinese (GB) equivalent of ASTM A194 Grade 7?
The nearest Chinese equivalent is 42CrMo (GB/T 3077), formerly 42CrMo. Equivalents are close but not identical — compare chemistry and properties before substituting.
What is the JIS equivalent of ASTM A194 Grade 7?
The nearest Japanese (JIS) equivalent is SCM440 / SNB7 (JIS G4107).
Does Teshi Group supply ASTM A194 Grade 7?
Teshi Group manufactures stud bolts and nuts in this grade. Send your size, rating and quantity to info@teshigroup.com for a quotation with EN 10204 3.1 certificates.
Related products, data sheets and standards
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