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
ASME B18.2.4.6M Metric Heavy Hex Nuts – Dimensions, Specifications & Standards
Metric Heavy Hex Nuts for High-Load Pressure & Structural Bolting.
ASME B18.2.4.6M Metric Heavy Hex Nuts are metric-series internally threaded fasteners with a larger and taller profile compared to standard metric hex nuts, providing greater bearing surface area and superior resistance to embedment and rotation under heavy clamping loads — preferred for use with heavy hex stud bolts and heavy hex screws in pressure flange, structural steel, and heavy machinery applications. The standard defines metric dimensions for width across flats, width across corners, nut height, chamfer angle, and thread pitch tolerances. These nuts are used in bolted joints per ASTM A1014/A1014M for UNS N07718 (Inconel 718), where the nut must match the corrosion resistance and high-temperature strength of the paired bolting. ASTM A194 is the primary material specification, covering grades from carbon steel to high-alloy materials. The larger bearing surface is especially valuable in soft flange materials where standard nuts could cause embedment.
ASME B18.2.4.6M Metric Heavy Hex Nuts Dimensions (mm)
| Nominal Dia. | Width Across Flats, S | Width Across Corners, E | Thickness, M | Bearing Face Dia., Dw | Washer Face Thickness, C | Total Runout of Bearing Surface FIM | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| Max. | Min. | Max. | Min. | Max. | Min. | Min. | Max. | Min. | Max. | |
| M12 | 21.00 | 20.16 | 24.25 | 22.78 | 12.3 | 11.9 | 19.2 | 0.8 | 0.4 | 0.38 |
| M14 | 24.00 | 23.16 | 27.71 | 26.17 | 14.3 | 13.6 | 22.0 | 0.8 | 0.4 | 0.42 |
| M16 | 27.00 | 26.16 | 31.18 | 29.56 | 17.1 | 16.4 | 24.9 | 0.8 | 0.4 | 0.47 |
| M20 | 34.00 | 33.00 | 39.26 | 37.29 | 20.7 | 19.4 | 31.4 | 0.8 | 0.4 | 0.58 |
| M22 | 36.00 | 35.00 | 41.57 | 39.55 | 23.6 | 22.3 | 33.3 | 0.8 | 0.4 | 0.63 |
| M24 | 41.00 | 40.00 | 47.34 | 45.20 | 24.2 | 22.9 | 38.0 | 0.8 | 0.4 | 0.72 |
| M27 | 46.00 | 45.00 | 53.12 | 50.85 | 27.5 | 26.3 | 42.8 | 0.8 | 0.4 | 0.80 |
| M30 | 50.00 | 49.00 | 57.74 | 55.37 | 30.7 | 29.1 | 45.6 | 0.8 | 0.4 | 0.87 |
| M36 | 60.00 | 58.80 | 69.28 | 66.44 | 36.6 | 35.0 | 55.9 | 0.8 | 0.4 | 1.05 |
| M42 | 70.00 | 67.90 | 80.83 | 77.41 | 42.0 | 40.4 | 64.5 | 1.0 | 0.5 | 1.22 |
| M48 | 80.00 | 77.60 | 92.38 | 88.46 | 48.0 | 46.4 | 73.7 | 1.0 | 0.5 | 1.40 |
| M56 | 90.00 | 87.20 | 103.92 | 99.41 | 56.0 | 54.1 | 82.8 | 1.0 | 0.5 | 1.57 |
| M64 | 100.00 | 96.80 | 115.47 | 110.35 | 64.0 | 62.1 | 92.0 | 1.0 | 0.5 | 1.75 |
| M72 | 110.00 | 106.40 | 127.02 | 121.30 | 72.0 | 70.1 | 101.1 | 1.2 | 0.6 | 1.92 |
| M80 | 120.00 | 116.00 | 138.56 | 132.24 | 80.0 | 78.1 | 110.2 | 1.2 | 0.6 | 2.09 |
| M90 | 135.00 | 130.50 | 155.88 | 148.77 | 90.0 | 87.8 | 124.0 | 1.2 | 0.6 | 2.36 |
| M100 | 150.00 | 145.00 | 173.21 | 165.30 | 100.0 | 97.8 | 137.8 | 1.2 | 0.6 | 2.62 |
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