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
A286 Metric Screws
A286 metric screws are the European / Asian / Indian-spec precision-hardening fasteners covering all socket-drive and external-drive screw configurations in metric sizes M3-M48. TorqBolt manufactures A286 metric screws to ISO 4762 / DIN 912 (socket head cap), ISO 7380 / DIN 7380 (button head socket), ISO 10642 / DIN 7991 (flat head countersunk socket), DIN 7984 (low-head SHCS), DIN 933 / ISO 4017 (hex external), and DIN 963 / ISO 2009 (slotted countersunk) standards. Coarse-pitch threads per ISO 261 default, fine-pitch available for vibration-critical applications. Heat-treated to ASTM A453 grade 660 Class A from AMS 5731 / 5732 bar, 895 MPa tensile, 655 MPa yield. See parent A286 screws, sister variants SHCS, flat head screws, button head screws, cap screws, and the canonical A286 chemical composition, heat treatment.
About A286 Metric Screws
TorqBolt produces metric A286 screws across the full ISO / DIN screw-standard family. Metric is the dominant standard in European aerospace (Airbus, Eurocopter, Snecma), Asian aerospace (Mitsubishi, KAI, HAL), Indian power and steel industries, and global automotive (BorgWarner, Garrett, Bosch). Each metric A286 screw is cold-headed from A286 bar (AMS 5731), drive form punched or broached per ISO standard (hex socket per ISO 2936, Phillips per DIN 7984, Torx per ISO 10664), thread-rolled to ISO 1502 6g tolerance (commercial) or 4g6g (aerospace), solution-treated 1650 °F + aged 1325 °F × 16 h, passivated per ASTM A967 Type II, head-stamped 'A286' + 'GR 660' (per ASTM F788) + lot + 'TB'.
A286 Metric Screw Standards & Configurations
TorqBolt produces metric A286 screws in seven primary configurations:
- ISO 4762 / DIN 912 (socket head cap), Cylindrical head, internal hex socket, the canonical metric SHCS. M3-M48 sizes, the most common metric A286 screw.
- ISO 7380 / DIN 7380 (button head socket), Low-profile dome head, internal hex socket, decorative and low-clearance applications. M3-M16 sizes.
- ISO 10642 / DIN 7991 (flat head 90° countersunk socket), 90° countersunk flat head, internal hex socket, flush-mount industrial and commercial. M3-M30.
- DIN 7984 (low-head SHCS), Reduced-height socket head, for limited axial clearance applications. Lower preload than ISO 4762, requires knurled hex bit.
- DIN 933 / ISO 4017 (hex external head), External hex full-thread machine screw, for general assembly and ventilation hardware in M3-M16 sizes.
- DIN 7985 / ISO 7045 (pan head Phillips), Pan head with Phillips drive, light-load assembly, commercial industrial applications. M3-M10.
- DIN 963 / ISO 2009 (flat head slotted), 90° slotted flat head, legacy commercial standard, still used in machinery overhaul and older drawings.
A286 Metric Screw Sizes & ISO Reference
| Metric size | Pitch | ISO 4762 head ⌀ | Hex socket | ISO 7380 head ⌀ | ISO 10642 head ⌀ | Min. tensile (kN) |
|---|---|---|---|---|---|---|
| M3 | 0.5 | 5.5 mm | 2.5 mm | 5.7 mm | 6.0 mm | 2.5 |
| M4 | 0.7 | 7.0 mm | 3 mm | 7.6 mm | 8.0 mm | 4.5 |
| M5 | 0.8 | 8.5 mm | 4 mm | 9.5 mm | 10.4 mm | 7.2 |
| M6 | 1.0 | 10.0 mm | 5 mm | 10.5 mm | 12.6 mm | 10.2 |
| M8 | 1.25 | 13.0 mm | 6 mm | 14.0 mm | 17.6 mm | 18.6 |
| M10 | 1.5 | 16.0 mm | 8 mm | 17.5 mm | 21.0 mm | 29.4 |
| M12 | 1.75 | 18.0 mm | 10 mm | 21.0 mm | 25.0 mm | 42.8 |
| M16 | 2.0 | 24.0 mm | 14 mm | 33.6 mm | 79.8 | |
| M20 | 2.5 | 30.0 mm | 17 mm | 124.5 |
A286 Metric Screws Manufacturing Process
Every a286 metric screws TorqBolt ships traces back to a vacuum-induction-melted plus vacuum-arc-remelted (VIM-VAR) ingot meeting AMS 5731 / 5732 chemistry. The complete process route:
- VIM-VAR melt sourcing: AMS 5731 / 5732 chemistry. ISO 9001 + AS9100D for aerospace lots.
- Vacuum-degassed bar (aerospace): Aerospace metric A286 uses vacuum-degassed input bar for fatigue performance.
- Cold heading (sizes ≤ M16): Multi-station bolt-maker forms head + cone + drive in one cycle per ISO 4762 / 7380 / 10642 dimensions.
- Hex socket cold-forging: Hex socket forged in head-stroke for ISO 4762 / 7380 / 10642, depth ≈ 0.5 × head height per ISO 2936.
- Thread rolling 6g (commercial) or 4g6g (aerospace): Cylindrical or flat-die rolling to ISO 1502 6g (commercial) or 4g6g (aerospace MIL-S-8879 equivalent).
- Solution treatment: Vacuum 1650 °F (899 °C) per AMS 5737 / ASTM A453 Class A; 1 hour per inch, oil-quench.
- Precipitation aging: 1325 °F (718 °C) for 16 hours, air-cool. Aerospace lots ±5 °C control.
- Passivation per ASTM A967: Pickle + HNO₃ rinse + passivate Type II. Optional silver / nickel anti-galling coat for above-540 °C service.
- Marking + pack: Head-stamped 'A286' + 'GR 660' (per ASTM F788) + lot + 'TB'. Bulk pack 100 / 250 / 500 pcs.
A286 Metric Screws Inspection & Certification
Each lot ships with a signed inspection certificate. Aerospace orders are released with AS9102 first-article inspection per AS9100D AQMS. Industrial orders default to EN 10204 type 3.1; sour-service and offshore step up to type 3.2 with third-party witness.
- 100 % thread-gauge GO/NO-GO per ISO 1502 (commercial) or MIL-S-8879 (aerospace).
- 100 % hex socket dimension per ISO 2936 (ISO 4762 / 7380 / 10642).
- Head ⌀ and head height verified by snap gauge per ISO standard.
- Hardness traverse 4-point Vickers per heat-treat batch.
- Magnetic permeability < 1.005 per ASTM A342 on every aerospace coil.
- Tensile coupon per ISO 6892-1 from each heat.
- AS9102 first-article on aerospace lots; EN 10204 3.1 mill cert standard for industrial.
- Salt-spray ASTM B117 96-hour pass for passivated lots.
A286 Metric Screws Torque & Assembly Practice
Metric A286 screws torque to 75 % of room-temperature 0.2 % yield (~ 490 MPa residual stress for grade 660 Class A) for static joints, 60 % for cycling joints. Common torque values M6 ISO 4762: 8 N·m oil / 6 N·m anti-seize. M8: 18 N·m oil / 13 N·m anti-seize. M10: 35 N·m oil / 25 N·m anti-seize. M16: 180 N·m oil / 130 N·m anti-seize. Above 540 °C apply nickel or copper anti-seize per AS5272. ISO 16047 friction-coefficient testing standard for high-temperature metric joints.
A286 Metric Screw Applications by Industry
Metric A286 screws are the dominant non-US aerospace and industrial fastener:
- European aerospace (Airbus / Eurocopter): ISO 4762 SHCS on Airbus A320 / A330 / A350 engine accessory and structural attach. Eurocopter Tiger / NH90 rotor head bolting.
- Asian aerospace (Mitsubishi / HAL / KAI): ISO 4762 SHCS on Mitsubishi MRJ engine assembly, HAL Tejas accessory mounting, KAI T-50 structural.
- Industrial gas turbines (Siemens / MAN / BHEL): ISO 4762 M8-M20 SHCS on combustor liner attachment, exhaust diffuser bolting. A286 gas turbine applications.
- Automotive turbocharger: ISO 7380 button-head and ISO 10642 flat-head A286 on Garrett, BorgWarner, IHI turbocharger assemblies, exhaust-housing bolting.
- Marine diesel / LNG: ISO 4762 M10-M24 SHCS on MAN B&W, Wärtsilä, MTU diesel engine exhaust valve and turbocharger.
- Indian power generation: BHEL gas-turbine and steam-turbine assembly with M8-M30 ISO 4762 metric A286 SHCS.
Governing Standards & Material Specifications
Every A286 fastener is released against the applicable industry standard. EN 10204 type 3.1 mill certificates ship with every order. See the consolidated A286 AMS / ASTM specifications hub for full spec scope.
| Authority | Specification | Coverage |
|---|---|---|
| ASTM | A453 grade 660 Cl. A/B/C/D | High-temperature bolting material |
| ASTM | A638 grade 660 Type 1/2 | Forged bolting stock |
| AMS | 5731 | Bar / forging, solution-treated |
| AMS | 5732 | Bar / forging, solution-treated and aged |
| AMS | 5737 | Bar, solution-treated and aged (precision) |
| UNS | S66286 | Material designation |
| DIN | 1.4980 / X5NiCrTiMoVB25-15-2 | European designation |
| EN | 10204 3.1 / 3.2 | Mill / third-party-witness certification |
| NACE | MR0175 / ISO 15156-3 | Sour-service hardness limit ≤ HRC 35 |
A286 Metric Screws vs Alternative Materials
When selecting a fastener material engineers compare A286 against three alternatives: A286 vs Inconel 718 (top-end performance, 3× cost), A286 vs 17-4 PH (cheaper but limited to 315 °C), and A286 vs Waspaloy (sustained service > 700 °C). A286 is the cost-performance leader for non-magnetic precipitation-hardening service in the 540-700 °C envelope. See the consolidated A286 equivalent grades reference for full alloy alternatives.
How to Specify A286 Metric Screws
A complete a286 metric screws callout should include: material spec, heat-treatment condition, dimensional standard, size, thread tolerance class, surface finish, marking, inspection certificate. Example callout:
Socket head cap screw, ISO 4762, A286 (UNS S66286), ASTM A453 grade 660 Class A, ST+A, M10 × 1.5 × 50 mm, 6g, passivated, head-stamped ‘A286’ + ‘GR 660’ + lot + ‘TB’, EN 10204 3.1.
A286 Metric Screws, Frequently Asked Questions
What's the difference between A286 metric screws and A286 inch screws?
Material is identical (UNS S66286 / ASTM A453 grade 660). Thread system differs: metric uses M-designation (M3-M48) per ISO 1502 with mm pitch; inch uses UNC / UNF / 8-UN per ASME B1.1 with TPI. Wrench/hex-socket sizes also differ, metric in mm, inch in fractional inches.
What is the standard hex socket size for an A286 metric SHCS?
Per ISO 2936: M3=2.5mm, M4=3mm, M5=4mm, M6=5mm, M8=6mm, M10=8mm, M12=10mm, M16=14mm, M20=17mm, M24=19mm, M30=22mm, M36=27mm. Always check the drawing, some aerospace specs use non-standard hex socket sizes.
ISO 4762 vs DIN 912, which standard is current?
Functionally identical for M3-M48. ISO 4762 is the current international standard; DIN 912 was the German pre-cursor (still cited on older European drawings). Modern drawings cite ISO 4762; both result in identical screw dimensions.
Are metric A286 screws available in fine pitch?
Yes, TorqBolt manufactures metric fine-pitch A286 screws in M8 × 1.0, M10 × 1.25, M12 × 1.25 / 1.5, M14 × 1.5, M16 × 1.5, M18 × 1.5, M20 × 1.5, M22 × 1.5, M24 × 2.0. Used on aerospace and instrumentation high-vibration applications.
What is the most common metric A286 screw type?
ISO 4762 / DIN 912 socket head cap screw, accounts for ~70 % of metric A286 screw orders. Hex-socket internal drive, cylindrical head, M3-M48 size range.
Are metric A286 screws magnetic?
No. Magnetic permeability < 1.005 verified per ASTM A342 on every aerospace coil. Suitable for instrumentation, MRI, magnetometer, and electromagnetic-sensitive applications.
Can metric A286 screws pair with non-A286 metric nuts?
Mechanically yes, but galling above 540 °C is a concern for austenitic-stainless mating. Match A286 screws to A286 hex nuts for matched preload, magnetic permeability, and anti-galling protection.
What head-marking on a metric A286 screw?
Per ASTM F788 (TorqBolt convention): head-stamped 'A286' + 'GR 660' for ASTM A453 traceability + lot + manufacturer 'TB'. ISO marking does not specify grade markings; TorqBolt adds them voluntarily.
What's the longest metric A286 screw available?
ISO 4762 SHCS: standard to 200 mm in M3-M16, 300 mm in M20-M48. ISO 7380 button head: standard to 100 mm in M3-M16. ISO 10642 flat head: standard to 80 mm in M3-M30. Custom-drawing parts longer.
Why TorqBolt for A286 Metric Screws
Three reasons aerospace and gas-turbine OEMs place a286 metric screws orders with us:
- Vertically integrated supply, VIM-VAR melt sourcing from approved AMS-conforming mills, in-house cold heading + thread rolling + vacuum heat-treatment.
- Aerospace AQMS, AS9100D-certified factory in Mumbai with published quality manual covering A286 fastener-specific failure-mode analysis.
- Lead time discipline, 4-6 weeks for ASTM A453 grade 660 standard sizes, 8-12 weeks for custom-drawing aerospace parts.
Three decades of fastener manufacturing experience; current certifications: ISO 9001:2015, AS9100D, PED 2014/68/EU, NORSOK M-650 QTR.
Recent A286 Metric Screws Order Patterns
TorqBolt's metric A286 screw order book covers ISO 4762 SHCS for aerospace engine accessory mounting, ISO 7380 button-head for automotive turbocharger waste-gates, ISO 10642 90° flat-head for hydraulic manifold covers, and DIN 933 hex external on industrial gas-turbine casings.
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