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 B18.2.3.3M Metric Heavy Hex Screws Dimensions
Wide-Head Metric Fasteners in SI Dimensions for High-Load Structural and Pressure Bolting on Global Projects.
ASME B18.2.3.3M Metric Heavy Hex Screws are metric-series fasteners featuring a larger and taller hexagonal head profile than standard metric hex screws, expressed in SI dimensions, specifically engineered for heavy-duty structural, pressure vessel, and industrial flange bolting applications on global projects where metric fastener standards are specified by engineering design codes and international procurement requirements. The ASME B18.2.3.3M standard defines all critical metric dimensions for head height, width across flats, width across corners, body diameter, thread pitch, thread length, and related tolerances, ensuring dimensional interchangeability and consistent clamping performance across all metric heavy hex screw suppliers worldwide. These metric heavy hex screws are manufactured to ASTM A1082, the specification for high-strength stainless steel bolting material, which ensures that corrosion resistance, tensile strength, and mechanical reliability of the fastener meet the demanding requirements of offshore platforms, desalination plants, LNG terminals, and coastal chemical facilities where saline atmospheric conditions accelerate corrosion attack on standard carbon steel fasteners. The larger bearing footprint of the heavy hex head reduces the risk of surface embedment in lower-strength base materials such as aluminium alloy flanges and GRP structures, maintaining bolt preload over extended service periods without the need for additional hardened washers. Specifying ASME B18.2.3.3M dimensions alongside ASTM A1082 material requirements provides a complete, globally recognized definition for metric heavy hex screw procurement.
| Nominal Dia., D ,andThreadPitch | Body Diameter.,D s | Width Across Flats,S | Width Across Corners, E | Head Height, K | Wrenching Height, K 1 | Washer Face Thickness,C | Washer FaceDia.,D w | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Max | Min | Max | Min | Max | Min | Max | Min | Min | Max | Min | Min | |
| M12 × 1.75 | 12 | 11.73 | 21 | 20.67 | 24.25 | 23.35 | 7.76 | 7.24 | 5.2 | 0.6 | 0.3 | 19.6 |
| M14 × 2 | 14 | 13.73 | 24 | 23.67 | 27.71 | 26.75 | 9.09 | 8.51 | 6.2 | 0.6 | 0.3 | 22.5 |
| M16 × 2 | 16 | 15.73 | 27 | 26.67 | 31.18 | 30.14 | 10.32 | 9.68 | 7 | 0.8 | 0.4 | 25.3 |
| M20 × 2.5 | 20 | 19.67 | 34 | 33 | 39.26 | 37.29 | 12.88 | 12.12 | 8.8 | 0.8 | 0.4 | 31.4 |
| M24 × 3 | 24 | 23.67 | 41 | 40 | 47.34 | 45.2 | 15.44 | 14.56 | 10.5 | 0.8 | 0.4 | 38 |
| M30 × 3.5 | 30 | 29.67 | 50 | 49 | 57.74 | 55.37 | 19.48 | 17.92 | 13.1 | 0.8 | 0.4 | 46.6 |
| M36 × 4 | 36 | 35.61 | 60 | 58.8 | 69.28 | 66.44 | 23.38 | 21.72 | 15.8 | 0.8 | 0.4 | 55.9 |
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Frequently Asked Questions
What stainless steel grades does ASTM A1082 cover for din 6914?
ASTM A1082 covers duplex grades (S31803/2205, S32205/2205, S32750/2507, S32760/Zeron 100, S39277/AL-6XN) and precipitation-hardening grades (S17400/17-4 PH, S17700/17-7 PH, S15700/15-7 PH, S35500/AM-355) - all available for this product family at TorqBolt.
What is the standard dimensional reference for these din 6914?
This product follows ASME B18.2 3 3M, the dimensional standard for din 6914 in stainless steel. Material chemistry, mechanical properties and heat treatment follow ASTM A1082/A1082M. TorqBolt supplies both inch-series and metric sizes per the applicable ASME or ISO drawing.
Are A1082 din 6914 suitable for sour service (NACE MR0175)?
Yes, with hardness control. NACE MR0175 / ISO 15156 permits duplex grades S31803, S32205, S32750, S32760 at 28 HRC max for sour service. 17-4 PH (S17400) at H1150 condition (28 HRC) is the most common PH grade qualified for sour service. TorqBolt provides NACE-MR0175 compliant heat-treat reports.
What is the typical strength of A1082 super-duplex 2507 (S32750) din 6914?
Super-duplex 2507 (S32750) per A1082: tensile 116 ksi (800 MPa) min, yield 80 ksi (550 MPa) min, elongation 15% min, 32 HRC max. PREN ≈ 42 - suitable for seawater, brine and chloride-rich pressure-vessel service. Higher strength than austenitic A193 B8M while offering pitting resistance well above 304/316.
References & Standards
- ASTM A1082 / A1082M - Standard Specification for High-Strength Precipitation-Hardening and Duplex Stainless Steel Bolting for Special-Purpose Applications (current edition 2016, active)
- ASTM A962 / A962M - General Requirements for Special-Purpose Bolting Materials
- ASTM A370 - Mechanical Testing of Steel Products
- NACE MR0175 / ISO 15156 - Sour-service hardness limits for petroleum & natural gas industries
- ASME B18 series - Dimensional standards for bolts, screws, nuts, studs
- ISO 4032 / 4033 / 4035 - Metric hexagon nut dimensional standards
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