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 B18.6.7M Metric Hex Head Machine Screws Dimension Standard
Versatile Metric Small Fasteners for Precision Electronics, Instrumentation, and Corrosion-Sensitive Industrial Assemblies.
ASME B18.6.7M Metric Hex Head Machine Screws are metric-series small fasteners designed to thread into pre-tapped holes or pair with metric nuts for securing components in electronics, control panels, scientific instruments, small mechanical assemblies, household appliances, and light industrial equipment where compact fastening and precise dimensional control are critical design requirements. The ASME B18.6.7M standard governs metric dimensions for multiple head styles including pan, flat, oval, truss, and binding heads — covering head diameter, head height, recess or slot dimensions, body diameter, thread pitch, thread length, and all associated tolerances in SI units for the complete metric machine screw size range. These metric machine screws are manufactured to ASTM A1082, the specification for high-strength stainless steel bolting material, which provides outstanding corrosion resistance, non-magnetic properties, and aesthetic surface quality required in medical devices, food-grade equipment, marine instrument panels, pharmaceutical packaging machinery, and chemical plant control cabinets. The fine thread pitches available in ASME B18.6.7M metric machine screws allow precise adjustment and controlled fastening in thin-walled components and precision assemblies where coarse thread fasteners would strip or provide insufficient holding strength in the base material. Full EN 10204 Type 3.1 material documentation is available for ASTM A1082 metric machine screws supplied to quality-critical projects in medical, aerospace, and industrial sectors.
| Nominal Size and Thread Pitch | DS | Sa | Ea | K | DA | R | |||
|---|---|---|---|---|---|---|---|---|---|
| Body Diameter | Hex Width Across Flats | Hex Width Across Corners | Head Height | Underhead Fillet | |||||
| Transition Dia | Radius | ||||||||
| Max | Min | Max | Min | Min | Max | Min | Max | Min | |
| M2 × 0.4 | 2 | 1.65 | 3.2 | 3.02 | 3.38 | 1.6 | 1.3 | 2.6 | 0.1 |
| M2.5 × 0.45 | 2.5 | 2.12 | 4 | 3.82 | 4.28 | 2.1 | 1.8 | 3.1 | 0.1 |
| M3 × 0.5 | 3 | 2.58 | 5 | 4.82 | 5.4 | 2.3 | 2 | 3.6 | 0.1 |
| M3.5 × 0.6 | 3.5 | 3 | 5.5 | 5.32 | 5.96 | 2.6 | 2.3 | 4.1 | 0.1 |
| M4 × 0.7 | 4 | 3.43 | 7 | 6.78 | 7.59 | 3 | 2.6 | 4.7 | 0.2 |
| M5 × 0.8 | 5 | 4.36 | 8 | 7.78 | 8.71 | 3.8 | 3.3 | 5.7 | 0.2 |
| M6 × 1 | 6 | 5.21 | 10 | 9.78 | 10.95 | 4.7 | 4.1 | 6.8 | 0.3 |
| M8 × 1.25 | 8 | 7.04 | 13 | 12.73 | 14.26 | 6 | 5.2 | 9.2 | 0.4 |
| M10 × 1.5 | 10 | 8.86 | 16 | 15.73 | 17.62 | 7.5 | 6.5 | 11.2 | 0.4 |
| M12 × 1.75 | 12 | 10.68 | 18 | 17.73 | 19.86 | 9 | 7.8 | 13.2 | 0.4 |
| M10 × 1.5b | 10 | 8.86 | 15 | 14.73 | 16.5 | 7.5 | 6.5 | 11.2 | 0.4 |
|
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Frequently Asked Questions
What stainless steel grades does ASTM A1082 cover for hex head machine screws?
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 hex head machine screws?
This product follows ASME B18.6 7M, the dimensional standard for hex head machine screws 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 hex head machine screws 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) hex head machine screws?
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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