INCONEL 718 BOLTS - UNS N07718 / W.NR. 2.4668
■ ASME B18.2.1 Heavy Hex Bolts (Imperial)
| NOMINAL DIA (Inches) |
DECIMAL EQUIV (Inches) |
WIDTH ACROSS FLATS (Basic) |
WIDTH ACROSS CORNERS (Min) |
HEAD HEIGHT (Basic) |
| 1/4" | 0.2500 | 1/2" | 0.556 | 11/64" |
| 5/16" | 0.3125 | 9/16" | 0.628 | 7/32" |
| 3/8" | 0.3750 | 11/16" | 0.768 | 1/4" |
| 7/16" | 0.4375 | 3/4" | 0.840 | 19/64" |
| 1/2" | 0.5000 | 7/8" | 0.982 | 11/32" |
| 5/8" | 0.6250 | 1-1/16" | 1.191 | 27/64" |
| 3/4" | 0.7500 | 1-1/4" | 1.403 | 1/2" |
| 7/8" | 0.8750 | 1-7/16" | 1.615 | 37/64" |
| 1" | 1.0000 | 1-5/8" | 1.826 | 43/64" |
| 1-1/8" | 1.1250 | 1-13/16" | 2.038 | 3/4" |
| 1-1/4" | 1.2500 | 2" | 2.249 | 27/32" |
| 1-1/2" | 1.5000 | 2-3/8" | 2.673 | 1" |
| 2" | 2.0000 | 3-1/8" | 3.520 | 1-11/32" |
Engineering Note: Heavy hex heads provide a significantly larger bearing surface across the flats compared to standard hex bolts, distributing the massive 150,000 psi yield clamp load generated by Inconel 718 to prevent flange crushing.
■ DIN 933 Metric Hex Bolts (mm)
| NOMINAL SIZE (D) |
PITCH (mm) |
WIDTH ACROSS FLATS (S) |
WIDTH ACROSS CORNERS (E) |
HEAD HEIGHT (K) |
| M6 | 1.00 | 10.00 | 11.05 | 4.00 |
| M8 | 1.25 | 13.00 | 14.38 | 5.50 |
| M10 | 1.50 | 17.00 | 18.90 | 7.00 |
| M12 | 1.75 | 19.00 | 21.10 | 8.00 |
| M16 | 2.00 | 24.00 | 26.75 | 10.00 |
| M20 | 2.50 | 30.00 | 33.14 | 13.00 |
| M24 | 3.00 | 36.00 | 39.98 | 15.00 |
| M30 | 3.50 | 46.00 | 51.28 | 19.00 |
| M36 | 4.00 | 55.00 | 61.31 | 23.00 |
■ Torque Specifications (Imperial)
| IMPERIAL DIA (TPI) |
TORQUE (LUBRICATED) ft-lbs |
TORQUE (DRY) ft-lbs |
| 1/4" - 20 | 12.0 | 16.2 |
| 5/16" - 18 | 24.9 | 33.1 |
| 3/8" - 16 | 44.1 | 58.8 |
| 1/2" - 13 | ~ 100.0 | ~ 130.0 |
| 5/8" - 11 | ~ 200.0 | ~ 260.0 |
| 3/4" - 10 | ~ 350.0 | ~ 450.0 |
| 1" - 8 | ~ 800.0 | ~ 1000.0 |
| 1-1/4" - 7 | 1598.0 | 2132.0 |
Warning: Inconel 718 bolts are exceptionally susceptible to thread galling. Dry installation frequently results in an erratic K-factor and severe thread seizure. Premium boundary lubricants (MoS2 pastes) or silver plating are strictly recommended.
■ Torque Specifications (Metric)
| METRIC SIZE |
MAX TORQUE (Nm) |
| M6 | 17.0 - 19.9 |
| M8 | 41.3 - 48.3 |
| M10 | 81.8 - 95.7 |
| M12 | 143.0 - 167.0 |
| M16 | 354.0 - 413.0 |
| M20 | 690.0 - 809.0 |
| M24 | 1195.0 - 1395.0 |
| M30 | 2377.0 - 2774.0 |
■ Estimated Mass & Structural Weight (Imperial)
| LENGTH (Under Head) |
1/2" DIA (lbs per 100) |
3/4" DIA (lbs per 100) |
1" DIA (lbs per 100) |
| 1-1/2" | 12.8 | 33.9 | 69.6 |
| 2" | 15.5 | 39.0 | 78.8 |
| 3" | 20.9 | 51.1 | 99.0 |
| 4" | 26.2 | 63.2 | 120.0 |
| 6" | 37.0 | 87.3 | 163.0 |
■ Estimated Mass & Structural Weight (Metric)
| METRIC SIZE |
WEIGHT (kg per 1000 Pcs) |
| M6 | 0.75 |
| M8 | 1.50 |
| M10 | 3.00 |
| M12 | 5.40 |
| M16 | 19.20 |
■ Bolt-Specific Technical Specifications
| MATERIAL & MATRIX |
Inconel 718 (UNS N07718). A precipitation-hardenable nickel-chromium-iron-molybdenum superalloy. Utilizes Niobium and Titanium to form gamma double-prime ($\gamma''$) and gamma prime ($\gamma'$) strengthening precipitates. |
| MECHANICAL INTEGRITY |
- Yield Strength (Min): 150,000 psi (1035 MPa)
- Tensile Strength (Min): 185,000 psi (1275 MPa)
- Hardness: 36 to 44 HRC (331 to 444 HBW)
|
| SPECIFICATIONS & HEAT TREATMENT |
- ASTM A1014: High-temperature bolting requirements ensuring extreme creep-rupture longevity.
- AMS 5662: Supplied solution-annealed for heavy machining and thread rolling.
- AMS 5663: Fully solution-annealed and precipitation age-hardened for maximum strength.
|
| THREAD FABRICATION (UN vs UNJ) |
For aerospace/critical industrial use, UNJ threads with an enlarged, controlled root radius are frequently specified to reduce stress concentrations. Rolling threads prior to aging highly refines the grain structure, increasing tension-tension fatigue life by up to 113% over cut threads. |
| ENVIRONMENTAL RESISTANCE |
Virtually immune to chloride SCC. Approved under NACE MR0175/ISO 15156 for sour gas ($H_2S$) service up to 40 HRC without risk of hydrogen embrittlement. Sustains loads safely up to 1300°F (704°C). |
