Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Incoloy 800H Hex Nuts
Incoloy 800H hex nuts are 6-sided threaded nuts machined from ASTM B408 round bar for matched-pair assembly with Incoloy 800H hex bolts, stud bolts and threaded rod in high-temperature petrochemical, refinery and fired-heater service to 815 deg C (1500 deg F). TorqBolt manufactures hex nuts to ASME B18.2.2 (inch) and DIN 934 (metric) dimensional standards in diameter range M12 to M48 (metric) and 1/2 inch to 1-7/8 inch (inch). The hex profile follows the DIN 934 across-flats schedule with controlled nut height per the standard. Internal threads are tapped to class 6H per ISO 965 (metric) or class 2B per ASME B1.1 (inch). Every hex nut ships with EN 10204 type 3.1 mill test certificate documenting heat number, ASTM B408 chemistry, solution-anneal cycle (1149 deg C plateau, rapid quench) and ASTM grain size 5 verification, with type 3.2 third-party witness supplied on call-out for refinery and offshore procurement.
Hex Nut Dimensions (DIN 934 / ASME B18.2.2)
| Size designation | Across flats / OD | Head / nut height | Thread pitch | Standard reference |
|---|---|---|---|---|
| M12 | 12.0 mm thread | A/F 19 mm; Nut height 10 mm | 1.75 mm (13 tpi UNC) | DIN 934 / ASME B18.2.2 |
| M16 | 16.0 mm thread | A/F 24 mm; Nut height 13 mm | 2.0 mm (11 tpi UNC) | DIN 934 / ASME B18.2.2 |
| M20 | 20.0 mm thread | A/F 30 mm; Nut height 16 mm | 2.5 mm (10 tpi UNC) | DIN 934 / ASME B18.2.2 |
| M24 | 24.0 mm thread | A/F 36 mm; Nut height 19 mm | 3.0 mm (9 tpi UNC) | DIN 934 / ASME B18.2.2 |
| M30 | 30.0 mm thread | A/F 46 mm; Nut height 24 mm | 3.5 mm (8 tpi UNC) | DIN 934 / ASME B18.2.2 |
| M36 | 36.0 mm thread | A/F 55 mm; Nut height 29 mm | 4.0 mm (7 tpi UNC) | DIN 934 / ASME B18.2.2 |
| M42 | 42.0 mm thread | A/F 65 mm; Nut height 34 mm | 4.5 mm (6 tpi UNC) | DIN 934 / ASME B18.2.2 |
| M48 | 48.0 mm thread | A/F 75 mm; Nut height 38 mm | 5.0 mm (5.5 tpi UNC) | DIN 934 / ASME B18.2.2 |
Manufacturing Route at TorqBolt
Hex nut manufacture is a CNC turn-mill operation from bar with through-hole drilling and thread tapping:
- Receive Incoloy 800H bar to ASTM B408; PMI verification.
- Cut bar into nut-height slugs on horizontal saw or CNC turn-cut.
- CNC mill the 6-sided hex profile per DIN 934 across-flats schedule.
- Drill the through-hole to thread-tap minor diameter.
- Tap the internal thread to class 6H per ISO 965 (metric) or class 2B per ASME B1.1 (inch).
- Solution anneal at 1149 deg C plateau followed by rapid quench; ASTM grain size 5 verified.
- Hardness band 120-184 HB on first piece and one per batch.
- Visual + dimensional + PMI inspection 100 percent; thread plug gauge verification.
- VCI wrap, pack with matched bolts or studs as per PO; CoC + EN 10204 cert.
Hex Nut Sizes Stocked and Lead Times
| Diameter range | Length range | Stock status | Lead time |
|---|---|---|---|
| M12 - M20 | Per DIN 934 | Stock + ex-stock | 7 working days |
| M24 - M30 | Per DIN 934 | Made-to-order from stock bar | 10 to 14 working days |
| M36 - M42 | Per DIN 934 | Made-to-order from stock bar | 14 to 21 working days |
| M48 | Per DIN 934 | Made-to-order, large bar | 3 to 5 weeks |
Inspection and Heat Marking
Hex nut specific inspections cover thread tap-quality, across-flats compliance and hardness control:
- Internal thread verified with class 6H plug gauge full-traverse.
- Across-flats verified with go / no-go gauge per DIN 934 schedule.
- Nut height verified to DIN 934 tolerance band.
- Hardness band 120-184 HB on first piece and one per batch.
- ASTM E112 grain-size etch verification (grain size 5 or coarser).
- PMI by X-ray fluorescence on first piece and one per batch.
- Visual inspection for thread damage and chamfer integrity.
- Heat number traceable to bar; batch CoC accompanies dispatch.
Typical Service Conditions
Hex nuts are the standard nut form on European-spec petrochemical and fired-heater flange assemblies:
- Matched assembly with DIN 931 hex bolts on European-spec flange bolting.
- Threaded rod end-nut anchoring on hanger and support construction.
- Stud bolt nut-end fastening where heavy-pattern nut is not required.
- U-bolt leg-end fastening on pipe-support clamps.
- Anchor bolt top-end fastening on structural anchoring.
- ASME Section VIII pressure-vessel manhole and instrument-nozzle bolting on European-spec scope.
Incoloy 800H Alloy Considerations on This Fastener Form
Companion Fasteners and Related Pages
- Heavy Hex Nuts: heavy-pattern ASME B18.2.2 alternative for pressure-vessel scope.
- Lock Nuts: prevailing-torque variant when vibration-resistance is required.
- Castle Nuts: cotter-pin retention variant for safety-wire applications.
- Wing Nuts: hand-tightened variant for inspection-cover bolting.
- Hex Bolts: matched bolts for hex nut assemblies.
Frequently Asked Questions
Q. What is the difference between DIN 934 and DIN 936?
DIN 934 is a standard hex nut with nut height approximately 0.8d. DIN 936 is a thin hex nut (also called jam nut) with reduced nut height approximately 0.5d, used as a locking nut on top of a primary nut.
Q. Are Incoloy 800H hex nuts qualified to ASTM A194 grade 8M?
No. A194 grade 8M is 316 stainless. Incoloy 800H is a separate nickel-iron-chromium alloy specified under ASTM B408. The certificate references B408 chemistry, not A194 chemistry.
Q. What is the thread tap class supplied?
Class 6H internal thread per ISO 965 default for metric supply. Class 2B per ASME B1.1 default for inch supply. Class 5H or 6H on PO call-out for special applications.
Q. Can hex nuts be supplied with washer face?
Yes. DIN 934 default includes washer face on one side. DIN 934-S (washer face both sides) is supplied on PO call-out.
Q. Do you supply matched-pair sets (bolt + nut + washer)?
Yes. Default supply on hex nut purchase is the nut only. Matched-pair sets are supplied when ordered with the bolt or stud line item from the same heat batch.
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