Related 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
MS14181 Bolts, Inconel 718 220 KSI Spline-Drive Flanged Head
Military Standard Nickel Alloy 718 Tension Bolts / External Wrenching / Aerospace Procurement
MS14181 is the United States military standard for high-strength tension bolts manufactured in nickel-alloy UNS N07718 (Inconel 718). The standard specifies a 220 ksi tensile strength, external wrenching spline-drive head, flanged shank-head transition, and dash-numbered sizes from 1/4 to 1-1/2 inch. The MS14181 family supersedes to NASM14181 under the National Aerospace Standard (NAS) consolidation. These bolts are the preferred fastener for gas-turbine compressor disc attachment, missile structural joinery, and high-cycle-fatigue aerospace bolted joints.
Quoting MS14181: send the full dash number (e.g. MS14181-5, MS14181-12, etc.), required grip length, drilled or non-drilled head, and ITAR clearance to info@torqbolt.com or call +91-22-66157017.
What is MS14181
MS14181 originated as a U.S. Air Force Military Standard for tension fasteners in supersonic airframe and turbine engine applications. The bolts are characterized by:
- Material: nickel-alloy UNS N07718 (Inconel 718), age-hardened
- Ultimate tensile strength: 220 ksi (1515 MPa) minimum
- Service temperature: -65 °F to +1200 °F
- Head style: external wrenching, 12-spline drive, flanged shank-head transition
- Thread form: UNJF-3A (rounded thread root for improved fatigue)
- Surface finish: passivated per AMS 2700
- Identification: head-marked with manufacturer ID + "718"
MS14181 Sizes & Dash Numbers
| Nominal Size | Thread | Dash Number Range |
|---|---|---|
| 1/4 inch | 1/4-28 UNJF-3A | MS14181-04 through MS14181-04xxx |
| 5/16 inch | 5/16-24 UNJF-3A | MS14181-05 through MS14181-05xxx |
| 3/8 inch | 3/8-24 UNJF-3A | MS14181-06 through MS14181-06xxx |
| 7/16 inch | 7/16-20 UNJF-3A | MS14181-07 through MS14181-07xxx |
| 1/2 inch | 1/2-20 UNJF-3A | MS14181-08 through MS14181-08xxx |
| 9/16 inch | 9/16-18 UNJF-3A | MS14181-09 through MS14181-09xxx |
| 5/8 inch | 5/8-18 UNJF-3A | MS14181-10 through MS14181-10xxx |
| 3/4 inch | 3/4-16 UNJF-3A | MS14181-12 through MS14181-12xxx |
| 7/8 inch | 7/8-14 UNJF-3A | MS14181-14 through MS14181-14xxx |
| 1 inch | 1-12 UNJF-3A | MS14181-16 through MS14181-16xxx |
The numeric portion following the dash encodes nominal diameter in sixteenths of an inch. The 'xxx' suffix encodes grip length in thirty-seconds of an inch and drilled-head suffix.
NASM14181 Supersession
Under the Aerospace Industries Association consolidation initiative, MS14181 was superseded by NASM14181 (National Aerospace Standard, derived from NAS, AS, and MS sources). For active procurement, NASM14181 is the current revision; legacy MS14181 part numbers remain valid for spare-parts inventory.
Equivalent + Related Aerospace Specs
| Standard | Scope |
|---|---|
| MS14181 / NASM14181 | UNS N07718 tension bolts, 220 ksi, external wrenching spline drive |
| AS3418 | Similar SAE Aerospace standard, 12-point double-hex head |
| NAS1351 | UNS N07718 socket-head cap screws, lower strength |
| SAE AS 7467 | Procurement specification for UNS N07718 bolts and screws, 185 ksi |
| SAE AMS 5663 | Material specification for UNS N07718 bar (precipitation hardened) |
| SAE AMS 2700 | Passivation of corrosion-resistant steels (surface finish) |
Manufacturing & Quality Control
MS14181 bolts are typically produced by:
- Vacuum-melted UNS N07718 bar to SAE AMS 5662 (solution treated) feed
- Hot or cold heading to form the flanged spline-drive head
- Roll-formed threads after solution annealing per ASTM A1014 §5.4
- Solution treatment + double age per SAE AMS 2774
- Passivation per SAE AMS 2700
- Magnetic-particle or fluorescent penetrant inspection
- Lot-traceable certification with mill test report + heat-treat charts
Related Inconel 718 Bolt Pages
- Full Inconel 718 properties reference
- Inconel 718 heat treatment cycle
- UNS N07718 chemistry hub
- Inconel 718 Socket Head Cap Screws (B18.3)
- Inconel 718 Heavy Hex Bolts (B18.2.1)
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