Standards
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
AS3216 superalloy 12-point bolts
AS3216 is the SAE Aerospace Standard for 180 ksi superalloy 12-point external-drive aerospace bolts. It is widely used in turbine-section bolting, jet-engine hot-section structures, and rocket-engine assembly because the 180 ksi tensile rating combined with high-temperature alloys (Inconel 718, Waspaloy, A286) survives the 700 °C service envelope and creep-rupture loading typical of turbine bolting. AS3216 is the higher-strength counterpart to MS21250 (160 ksi) and is typically produced in Inconel 718 (UNS N07718) for the highest-temperature service.
TorqBolt manufactures AS3216 bolts in Inconel 718, A286, Waspaloy, MP35N and Custom 465 to AS9100D Rev D and ISO 9001:2015 quality systems, with NORSOK M-630 and NACE MR0175 / ISO 15156 qualifications for sour-service offshore applications. Each bolt head carries the struck tB manufacturer ligature plus the alloy grade marking (INCO 718, A286, etc.), and every lot ships with a mill test report (MTC 3.1 standard, MTC 3.2 critical with third-party witness inspection of chemistry, hardness, tensile, and creep-rupture qualification records where applicable).
Common Alloys for AS3216
| Alloy | Tensile | Service envelope |
|---|---|---|
| A286 (UNS S66286) | 160 ksi | up to 700 °C |
| Inconel 718 (UNS N07718) | 180 ksi | up to 700 °C, jet-engine |
| AISI 8740 chromoly | up to 220 ksi (HT) | standard high-strength |
| Ti-6Al-4V (Grade 5) | 130 ksi | 56% lighter than steel |
UNJ-3A External Thread Dimensions (Common 12-Point Bolt Sizes)
Per SAE AS8879 (controlled-root-radius UNJ external thread). 12-point aerospace bolts under MS21250, NAS1351, AS3216, NAS6303 to NAS6320 are produced to UNJ-3A external thread tolerances. Root radius 0.150 P to 0.180 P (where P = pitch) for fatigue resistance, this is the difference vs standard UN-3A and the reason aerospace specifies UNJ.
| Nominal | TPI | Pitch P (mm) | Major Dia Min (mm) | Major Dia Max (mm) | Pitch Dia Min (mm) | Pitch Dia Max (mm) | Minor Dia Min (mm) | Minor Dia Max (mm) |
|---|---|---|---|---|---|---|---|---|
| 1/4-28 UNJF-3A | 28 | 0.907 | 6.297 | 6.350 | 5.706 | 5.770 | 5.156 | 5.296 |
| 5/16-24 UNJF-3A | 24 | 1.058 | 7.875 | 7.938 | 7.185 | 7.249 | 6.553 | 6.711 |
| 3/8-24 UNJF-3A | 24 | 1.058 | 9.462 | 9.525 | 8.773 | 8.840 | 8.139 | 8.298 |
| 7/16-20 UNJF-3A | 20 | 1.270 | 11.051 | 11.113 | 10.227 | 10.297 | 9.467 | 9.652 |
| 1/2-20 UNJF-3A | 20 | 1.270 | 12.638 | 12.700 | 11.815 | 11.887 | 11.051 | 11.243 |
| 9/16-18 UNJF-3A | 18 | 1.411 | 14.225 | 14.288 | 13.310 | 13.385 | 12.466 | 12.673 |
| 5/8-18 UNJF-3A | 18 | 1.411 | 15.812 | 15.875 | 14.897 | 14.973 | 14.054 | 14.262 |
| 3/4-16 UNJF-3A | 16 | 1.588 | 18.991 | 19.050 | 17.961 | 18.040 | 17.018 | 17.246 |
| 7/8-14 UNJF-3A | 14 | 1.814 | 22.166 | 22.225 | 21.001 | 21.085 | 19.926 | 20.181 |
| 1-12 UNJF-3A | 12 | 2.117 | 25.336 | 25.400 | 23.974 | 24.064 | 22.717 | 22.985 |
| 1 1/4-12 UNJF-3A | 12 | 2.117 | 31.687 | 31.750 | 30.328 | 30.418 | 29.072 | 29.343 |
| 1 1/2-12 UNJF-3A | 12 | 2.117 | 38.037 | 38.100 | 36.678 | 36.768 | 35.422 | 35.693 |
| 1 15/16-12 UNJF-3A | 12 | 2.117 | 49.149 | 49.213 | 47.791 | 47.886 | 46.535 | 46.812 |
| 2-12 UNJF-3A | 12 | 2.117 | 50.737 | 50.800 | 49.378 | 49.473 | 48.122 | 48.399 |
Internal thread (UNJ-3B, mating nut) tolerances and metric M-J equivalents available on request. Send drawing or spec callout to info@torqbolt.com.
Request a Quote
Send drawing or PO line referencing AS3216 to info@torqbolt.com or call +91-22-66157017.
Related aerospace specs
For broader 12-point aerospace specification context, see also the parent aerospace fasteners hub and the full 12-point catalog, plus sibling specs:
- NAS1351, close-tolerance 12-point external-wrenching
- MS21250, 160 ksi 12-point external-drive aerospace bolt
- MIL-DTL-7838, legacy mil-spec, replaced by NAS series
- NAS6303, 3/16" body NAS 6300-series tension cap-screw
- NAS6304, 1/4" body NAS 6300-series tension cap-screw
- NAS6305, 5/16" body NAS 6300-series tension cap-screw
- NAS6308, 1/2" body NAS 6300-series tension cap-screw
- NAS6310, 5/8" body NAS 6300-series tension cap-screw
- NAS6312, 3/4" body NAS 6300-series tension cap-screw
- NAS6315, 15/16" body NAS 6300-series tension cap-screw
- NAS6320, 1-1/4" body NAS 6300-series tension cap-screw
- DIN 12-Point, European metric 12-point M5 to M30, grade 12.9
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