ASTM A194 Grade 7 Heavy Hex Nuts
ASTM A194 Grade 7 heavy hex nuts — quenched and tempered chromium-molybdenum alloy steel of the AISI 4140 type (C 0.37–0.49%, Cr 0.75–1.20%, Mo 0.15–0.25%), the high-strength alloy grade listed with grade 4 for A320 L7 stud assemblies. Hardness and proof-load rows are not tabulated in the collected sources and are not asserted.
Last updated: 2026-11
Specifications
Grade 7 is the chromium-molybdenum alloy member of ASTM A194: the collected grade table titles it "Quenched & tempered alloy steel hvy hex nut" and the chemistry row names the AISI 4140 type — carbon 0.37–0.49%, chromium 0.75–1.20% and molybdenum 0.15–0.25% — the classic Cr-Mo alloy whose through-hardening behaviour is why the grade serves high-strength alloy stud assemblies. In stud-bolt practice the collected pairing tables list grade 7, with grade 4, as the nut side for A320 L7 studs in cryogenic and low-temperature service. One transcription note for honesty: the collected source's silicon cell in the 7/7M row reads internally inconsistently ("0.15-0.035%"), so the silicon figure is shown here as the 0.15–0.35% band consistent with the row's other cells and should be verified on the mill certificate. The collected sources print no hardness or proof-load rows for grade 7, so none are asserted — take mechanical figures from the certificate against the size of record.
| Standard | ASTM A194 — Grade 7 (heavy hex pattern) |
|---|---|
| Material | Chromium-molybdenum alloy steel, AISI 4140 type, quenched and tempered |
| Chemistry | C 0.37–0.49%, Mn 0.65–1.10%, P max 0.04%, S max 0.04%, Si 0.15–0.35% (see transcription note), Cr 0.75–1.20%, Mo 0.15–0.25% |
| Transcription note | The collected silicon cell for the 7/7M row prints "0.15-0.035%" — internally inconsistent with the row format; rendered here as 0.15–0.35% and to be verified per mill certificate |
| Service pairing | Listed with grade 4 as the nut side for A320 L7 studs — cryogenic / low-temperature assemblies (collected pairing table) |
| Hardness / proof load | Not tabulated in the collected sources for grade 7 — confirm per mill certificate against the size of record |
Materials
- Chromium-molybdenum alloy steel (AISI 4140 type), quenched and tempered
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (ASTM A194 Grade 7 Heavy Hex Nuts) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
Is Grade 7 the same steel as the A320 L7 studs it pairs with?
It is the same alloy family — the AISI 4140-type chromium-molybdenum chemistry (C 0.37–0.49%, Cr 0.75–1.20%, Mo 0.15–0.25%) is printed for the nut grade on the collected table, and L7 is the low-temperature stud specification built on that chemistry. The pairing exists because nut and stud need compatible strength and toughness behaviour through the heat treatment each specification prescribes. Order both sides by their own designations — A320 L7 studs and A194 7 nuts — and require mill certificates for each; the collected sources print no mechanical rows for the nut grade itself.
Why is the silicon chemistry cell flagged on this page?
Honesty about source quality. The collected transcription of the A194 chemistry table prints the silicon cell in the 7/7M row as "0.15-0.035%" — a range with its lower bound above its upper bound, which cannot be read as printed. The band rendered here (0.15–0.35%) is the reading consistent with the format of the surrounding cells, but a chemistry figure reconstructed from a defective transcription is not the same as a verified one, so the page says so and directs the check to the mill certificate that ships with the nuts.
What is the MOQ and lead time for this nut type?
The minimum order quantity is 10,000 pieces. Stock items ship in 3–7 days; non-stock items are confirmed at quotation. Common diameters in this nut type are widely stocked; confirm the exact schedule against quantity and size mix at quotation.
What should an RFQ for this nut type state?
State the standard designation (for example DIN 985 or DIN 6923), nominal thread size and pitch (metric coarse unless fine pitch is required), material and strength pairing with the mating bolt, finish (plain, zinc, or hot-dip galvanized where compatible), required certificates such as a mill test report per EN 10204 3.1, and quantity per size — plus destination country.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support