For ASTM A194 2H heavy hex nut sourcing, the direct answer is: specify ASTM A194 Grade 2H, ASME B18.2.2 heavy hex dimensions, nominal size, thread series, finish, compatible stud or bolt grade, certificates, inspection scope, lot traceability, and export packing in the same RFQ. Do not quote "heavy hex nut" alone when the nuts are used with A193 B7 studs, structural bolting, or project-controlled assemblies.
Direct answer for import buyers
ASTM A194 Grade 2H is a common heavy hex nut grade for high-strength bolting assemblies, especially when paired with ASTM A193 B7 stud bolts. Buyers should treat the nut as part of a bolting set, not as a generic hardware item. The nut grade, thread, finish, and documents must match the project requirement and the mating stud or bolt.
A quote-ready RFQ line should read like this: ASTM A194 Grade 2H heavy hex nut, ASME B18.2.2 dimensions, 3/4 in UNC or 8UN thread as specified, plain or hot-dip galvanized finish, compatible with ASTM A193 B7 stud bolts, MTC and heat lot traceability required, pre-shipment inspection report, export cartons on pallets with line-item labels.
| RFQ field | What to write | Why it matters |
|---|---|---|
| Standard | ASTM A194 Grade 2H, ASME B18.2.2 heavy hex dimensions | Prevents suppliers from quoting standard hex nuts or unclear heavy-pattern nuts |
| Size and thread | Nominal diameter plus UNC, UNF, 8UN, or drawing thread | Controls fit with the mating stud or bolt |
| Pairing | A193 B7 stud bolt, structural bolt, or buyer drawing assembly | Lets the supplier check compatibility instead of quoting the nut alone |
| Finish | Plain, black, zinc plated, hot-dip galvanized, or project-approved coating | Affects thread fit, corrosion performance, and inspection scope |
| Documents | MTC, heat lot, hardness data, coating report when needed | Supports project approval and traceability |
| Packing | Cartons or bags on pallets with size, grade, finish, lot, and buyer item labels | Reduces mixed-size and mixed-grade receiving problems |
What makes a 2H heavy hex nut different?
A heavy hex nut has a larger body than a regular hex nut of the same nominal diameter. The extra bearing area and heavy pattern are important in high-strength bolting assemblies. ASTM A194 Grade 2H defines the nut material and mechanical requirements, while ASME B18.2.2 defines dimensional expectations for the heavy hex form.
For buyers, the practical point is simple: do not substitute a regular hex nut for a 2H heavy hex nut unless the engineer or project specification allows it. The product may look similar in a packing photo, but the dimensional pattern, marking, and intended service are different.
2H nuts and A193 B7 stud bolts
Many buyers source ASTM A194 2H nuts together with ASTM A193 B7 studs for flange bolting, pressure piping, valves, and industrial equipment. In this situation, price comparison should be based on the whole bolting set: stud length, thread series, two nuts per stud where required, finish, certificates, inspection, and packing.
| Assembly item | Typical buyer requirement | RFQ caution |
|---|---|---|
| Stud bolt | ASTM A193 B7, size, length, thread series, finish | Confirm whether the length is overall length and whether two nuts are included |
| Nut | ASTM A194 2H heavy hex nut, same thread as stud | Do not allow standard hex nuts unless approved by the specification |
| Washer | Flat washer or hardened washer where specified | Include washer grade and finish if the project requires washers |
| Documents | MTCs for studs and nuts, heat lot references, inspection report | Make sure certificates match the supplied lots and packing labels |
| Packing | Studs and nuts packed by size, grade, finish, and lot | Avoid mixed cartons when several similar sizes ship together |
Thread fit and finish choices
Thread fit is one of the easiest places for a 2H nut order to fail. The nut thread must match the stud or bolt thread series. UNC, UNF, and 8UN are not interchangeable purchasing details. If the drawing states 8UN for larger diameter studs, write 8UN clearly on every relevant line item.
Finish also needs early agreement. Plain finish may be suitable for some controlled industrial uses, while hot-dip galvanized or zinc plated nuts may be requested for corrosion protection. For galvanized assemblies, confirm the mating stud or bolt finish and thread allowance so the nut runs on correctly. Do not compare a plain 2H nut quote against a hot-dip galvanized 2H nut quote as if the scope is identical.
Inspection checklist before shipment
| Checkpoint | What to inspect | Buyer reason |
|---|---|---|
| Marking | Grade marking and manufacturer identification where applicable | Supports receiving checks and project traceability |
| Dimensions | Across flats, thickness, chamfer, and general heavy hex form | Confirms the supplied item is heavy hex pattern |
| Thread | Thread series, gauge check, and run-on test with matching studs if available | Prevents assembly delays at site |
| Documents | MTC, heat lot, hardness data, chemical and mechanical values | Connects the physical goods to the approved specification |
| Finish | Coating type, surface condition, rust, damage, and coating report if required | Reduces claims and installation issues |
| Packing | Quantity, labels, lot separation, carton strength, pallet condition | Protects mixed-size shipments during export and receiving |
Common sourcing mistakes
- Writing only "heavy hex nut" without ASTM A194 2H and ASME dimensional scope.
- Forgetting to state the thread series, especially when the mating stud is not UNC.
- Comparing nut-only quotes against quotes that include studs, washers, certificates, and packing.
- Assuming a regular hex nut can replace a heavy hex nut.
- Requesting certificates after production instead of including them in the RFQ.
- Letting mixed sizes ship with vague carton labels such as "nuts" or "2H nuts" only.
Practical Yongnian and Handan sourcing context
In the Yongnian and Handan fastener supply base, 2H nut orders may involve different specialist routes from B7 stud bolts, washers, coating, and export packing. That is normal for mixed project orders, but it means overseas buyers need one party to control specification matching, lot separation, inspection, and documents across the complete shipment.
HDBolt can coordinate ASTM A194 2H heavy hex nuts, ASTM A193 B7 stud bolts, flat washers, packaging, labels, and shipment documents under one export workflow. This is useful when a distributor or project buyer needs several diameters, thread series, finishes, and document sets in one purchase order.
RFQ wording buyers can copy
ASTM A194 Grade 2H heavy hex nut, ASME B18.2.2 dimensions, size 3/4 in, UNC thread, plain finish, for use with ASTM A193 Grade B7 stud bolts, MTC and heat lot traceability required, grade marking and dimensional inspection required, carton labels to show product, standard, grade, size, thread, finish, quantity, lot code, and buyer item number, export pallet packing, destination port included.
What HDBolt recommends
Buy 2H heavy hex nuts as a controlled bolting component, not as a commodity nut. Start with the project specification, match the thread to the stud or bolt, state the finish, require the documents before production, and inspect marking, dimensions, thread fit, and packing before shipment.
To request a quote, send your nut size list, thread series, finish, matching stud or bolt requirement, certificate needs, packing requirement, and destination through the HDBolt contact page. For broader procurement planning, review our China fastener sourcing guide, nut product category, and ASTM A193 B7 stud bolt RFQ guide.