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
Monel 400 Bolts (UNS N04400 / ASTM F468)
Procurement engineers reach for Monel 400 bolts when the joint sees hydrofluoric acid, flowing seawater, sour gas at NACE MR0175 limits, or a non-magnetic spec on a naval bulkhead. The bolt is covered by ASTM F468; chemistry comes from ASTM B164 bar; the alloy registers as UNS N04400. Bolts are manufactured in classes A (Ni 400, weldable) and B (Ni 405, free-machining). NACE MR0175 sour service is automatic when the F468 25 HRC hardness cap is met. Monel® is a registered trademark of Special Metals Corporation; TorqBolt is not authorized by, affiliated with or endorsed by Special Metals.
Scope of ASTM F468 for Monel 400
Imperial 1/4 inch through 1-1/2 inch (the F468 envelope). Metric M6 through M40 standard, M48 through M64 on indent through ASTM B564 forging stock with mechanicals matched to F468 Heavy Forged Equivalent. Threading per ASME B1.1 UNC and UNF, DIN 933 fully threaded, DIN 931 partial thread. Head forms: hex cap (most common), heavy hex, socket head cap (DIN 912 / ISO 4762), anchor (L, J, headed, swedged), stud (full thread, double end).
F468 Class A vs Class B
| Class | UNS | Sulfur (%) | F468 marking | Use case |
|---|---|---|---|---|
| A (Ni 400) | N04400 | 0.024 max | F 468U / F 468U4 / F 468HF | Weldable bolting; sour service; HF alky flanges |
| B (Ni 405) | N04405 | 0.025 to 0.060 | F 468V | Free-machining where joint stays unwelded |
Verified F468 Mechanical Property Minima
F468 sets the mechanical floor by nominal thread diameter. F468 hardness max is 25 HRC across all diameters, tighter than the NACE MR0175 35 HRC sour-service ceiling. Source: ASTM F468/F468M-2016 Table 2.
| Marking | Diameter (in) | Hardness | Tensile (ksi) | Tensile (MPa) | Yield min (ksi) | Yield min (MPa) | Elongation |
|---|---|---|---|---|---|---|---|
| F 468U | 0.250 to 0.750 | 75 HRB to 25 HRC | 80 to 130 | 552 to 896 | 40 | 276 | 20% |
| F 468U | 0.875 to 1.500 | 60 HRB to 25 HRC | 70 to 130 | 483 to 896 | 30 | 207 | 20% |
| F 468U4 | 0.875 to 1.500 | 75 HRB to 25 HRC | 80 to 130 | 552 to 896 | 40 | 276 | 20% |
| F 468HF | all | 60 to 95 HRB | 70 to 120 | 483 to 827 | 30 | 207 | 20% |
| F 468V (R-405) | all | 60 HRB to 20 HRC | 70 to 125 | 483 to 862 | 30 | 207 | 20% |
Sizing Matrix (Imperial UNC + UNF)
| Diameter (in) | UNC tpi | UNF tpi | Tensile area UNC (sq.in) | Stocked length (in) |
|---|---|---|---|---|
| 1/4 | 20 | 28 | 0.0318 | 1/2 to 6 |
| 3/8 | 16 | 24 | 0.0775 | 3/4 to 8 |
| 1/2 | 13 | 20 | 0.1419 | 3/4 to 10 |
| 5/8 | 11 | 18 | 0.226 | 1 to 12 |
| 3/4 | 10 | 16 | 0.334 | 1-1/4 to 12 |
| 7/8 | 9 | 14 | 0.462 | 1-1/2 to 14 |
| 1 | 8 | 12 | 0.606 | 2 to 16 |
| 1-1/4 | 7 | 12 | 0.969 | 2-1/2 to 18 |
| 1-1/2 | 6 | 12 | 1.405 | 3 to 20 |
Torque Reference (Yield-Based, K=0.20 Dry)
| Diameter | Preload at 75% F468 yield (lb) | Dry K=0.20 (ft-lb) | Lubricated K=0.16 (ft-lb) |
|---|---|---|---|
| 1/4 | 716 | 3 | 2.4 |
| 3/8 | 1744 | 11 | 8.8 |
| 1/2 | 3193 | 27 | 21 |
| 5/8 | 5085 | 53 | 42 |
| 3/4 | 7515 | 94 | 75 |
| 1 | 13635 | 227 | 182 |
| 1-1/4 | 21803 | 454 | 363 |
| 1-1/2 | 31613 | 790 | 632 |
Sour Service Compliance (NACE MR0175)
F468 caps hardness at 25 HRC; the NACE MR0175 ceiling for nickel-copper is 35 HRC. The bolt clears the hardness gate by design. Verify the H2S partial pressure and chloride concentration against ISO 15156-3 Annex A.4 for the full sour qualification. Sour-service shipments ship with EN 10204 type 3.2 plus the NACE compliance statement. Detail on sour service applications.
HF Alkylation and HF Storage
Monel 400 is the default bolting on HF-wetted flanges in HF alkylation units per API RP 751 inspection regime. The nickel-copper film resists HF attack across the alkylation acid concentration band (70 to 95 percent) where austenitic stainless and copper alloys fail. Detail on HF acid resistance and HF alkylation.
Companion Components
Monel 400 nuts to ASTM F467: hex, heavy hex, lock. Washers (DIN 125 plain, DIN 9021 fender, DIN 127 spring, DIN 6798 serrated). Threaded rod in 1 m and 3 m mill lengths. Pair the nut chemistry to the bolt to avoid galvanic discontinuity in the clamped joint.
Request for Quote
Send diameter, length, thread, head form, applicable spec and quantity to info@torqbolt.com or WhatsApp +91-22-66157017. Ex-Mumbai price and lead time returned within one working day. Domestic India 3 to 7 working days; export through JNPT.
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