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 Hex Bar
A286 hex bar is hexagonal-cross-section A286 bar stock used as raw input for hex nut, hex bolt, and hex-cross-section machined-component production. TorqBolt cold-draws A286 hex bar to AMS 5731 (sol-treated), AMS 5732 (sol-treated and aged), AMS 5737 (precision aged), and ASTM A453 grade 660 standards in across-flats sizes 8-65 mm. Distinguished from A286 round bar by the hexagonal cross-section that aligns to standard wrench sizes per ISO 272 / DIN 1915, feeds directly into the hex nut and hex bolt production line without secondary milling. Heat-treated per AMS 5732 / 5737 to deliver 130 ksi tensile / 95 ksi yield, retained mechanical properties to 700 °C continuous service. See parent A286 bar stock, sister variants A286 round bar, square bar, flat bar, and the canonical chemical composition + A286 mechanical-property data.
About A286 Hex Bar
A286 hex bar is produced by cold-drawing hot-rolled A286 round bar through a hexagonal die. The drawing operation simultaneously achieves three goals: (1) the round-to-hex cross-section transformation, (2) ±0.05-0.10 mm dimensional tolerance on across-flats, and (3) surface finish improvement (Ra typically 1-2 µm). Across-flats sizes match the standard ISO 272 hex nut wrench dimensions: 10 mm AF for M6, 13 mm for M8, 17 mm for M10, 19 mm for M12, 24 mm for M16, 30 mm for M20, 36 mm for M24, 46 mm for M30, 55 mm for M36, bar size is selected to match the finished nut wrench AF without secondary milling. Each lot is solution-treated and aged per AMS 5732 / 5737, then cut to length and heat-traceability labelled.
A286 Hex Bar Across-Flats Sizes & Production
A286 hex bar across-flats sizes match standard ISO 272 / DIN 1915 hex wrench dimensions for direct nut and bolt manufacture:
- 8-13 mm AF (M5-M8), Cold-drawn hex bar 8 mm, 10 mm, 13 mm AF, feeds M5, M6, M8 hex nut and hex-head fastener production lines. Tolerance ±0.05 mm AF.
- 17-24 mm AF (M10-M16), Cold-drawn 17, 19, 22, 24 mm AF, for M10, M12, M14, M16 fasteners. The highest-volume hex-bar-to-fastener size range.
- 27-36 mm AF (M18-M24), Cold-drawn 27, 30, 32, 36 mm AF, for M18 to M24 large fasteners and structural bolting.
- 41-65 mm AF (M27-M48), Hot-rolled then cold-drawn 41, 46, 50, 55, 60, 65 mm AF, for M27 to M48 heavy structural and pressure-vessel fasteners.
- Custom across-flats sizes, Non-standard AF dimensions on custom orders, used for specialty hex-cross-section machined parts (valve stems, hex-shafted couplings).
A286 Hex Bar Sizes & Tolerance Reference
| Across-flats | For mating nut | Bar tolerance | Across-corners (calculated) | Available specs |
|---|---|---|---|---|
| 8 mm | M5 | ±0.05 mm | 9.24 mm | AMS 5731 / 5732 / 5737 |
| 10 mm | M6 | ±0.05 mm | 11.55 mm | AMS 5731 / 5732 / 5737 |
| 13 mm | M8 | ±0.07 mm | 15.01 mm | AMS 5731 / 5732 / 5737 |
| 17 mm | M10 | ±0.07 mm | 19.63 mm | AMS 5731 / 5732 / 5737 |
| 19 mm | M12 | ±0.10 mm | 21.94 mm | AMS 5731 / 5732 / 5737 |
| 24 mm | M16 | ±0.10 mm | 27.71 mm | AMS 5731 / 5732 / 5737 |
| 30 mm | M20 | ±0.13 mm | 34.64 mm | AMS 5731 / 5732 |
| 36 mm | M24 | ±0.15 mm | 41.57 mm | AMS 5731 / 5732 |
| 46 mm | M30 | ±0.18 mm | 53.12 mm | AMS 5731 / 5732 |
| 55 mm | M36 | ±0.20 mm | 63.51 mm | AMS 5731 / 5732 |
A286 Hex Bar Manufacturing Process
Every a286 hex bar 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 round-bar input: Hot-rolled or hot-extruded A286 round bar to AMS 5731 / 5732 chemistry, diameter slightly oversize vs target hex AF (round ⌀ ≈ AF × 1.10) to allow drawing reduction.
- Surface preparation: Round bar surface pickled in HNO₃ + HF, dried, and lubricated with drawing soap for cold-die operation.
- Hex die cold drawing: Bar drawn through a hexagonal die at 0.5-1.0 m/min, single-pass for AF ≤ 30 mm, multi-pass for larger sizes. Drawing reduction 20-30 % per pass.
- Inter-pass annealing (large sizes): For multi-pass drawing of AF > 30 mm, intermediate solution annealing at 1650 °F restores ductility for the next drawing pass.
- Final solution treatment: Vacuum or atmosphere furnace 1650 °F (AMS 5737) or 1800 °F (AMS 5731 / 5732). 1 h per inch, oil-quench.
- Precipitation aging (AMS 5732 / 5737): 1325 °F for 16 hours, air-cool. Develops gamma-prime; hardness 29-32 HRC.
- Straightening: Drawn hex bar straightened on multi-roll straightener to ≤ 2 mm/m straightness tolerance.
- Across-flats inspection: 100 % AF dimensional check by snap gauge per ISO 272 / DIN 1915 tolerance, ±0.05 mm at 8 mm, ±0.20 mm at 55 mm.
- Cut to length + label: Bar cut to drawing length on band saw, end-faced, and heat-traceability labelled. Bulk pack on pallet.
A286 Hex Bar Inspection & Certification
Each lot ships with a signed inspection certificate. Aerospace orders default to AS9100D first-article reporting per AS9102. Industrial orders default to EN 10204 type 3.1; sour-service and offshore step up to type 3.2 with third-party witness. Inspection scope:
- Across-flats dimension verified by snap gauge per ISO 272 / DIN 1915 tolerance.
- Across-corners dimension verified by ring gauge or 6-point gauge.
- Straightness check per ASTM A484, typical ≤ 2 mm/m for cold-drawn hex bar.
- Surface inspection 100 % visual for drawing-die scoring, surface laps, edge rounding.
- Hardness sample 1 per heat per ASTM E384, 4-point Vickers on hex face.
- Tensile coupon from each heat per ASTM E8.
- Magnetic permeability < 1.005 per ASTM A342 on every aerospace heat.
- AS9102 first-article on aerospace heats; EN 10204 3.1 commercial heats with heat-traceability label.
A286 Hex Bar Downstream Forming & Machining
Hex bar is raw stock, torque does not apply directly. Downstream forging and machining: hot-upsetting force for M16 hex nut from 24 mm AF blank ≈ 200 kN; cold-heading force for M8 from 13 mm AF blank ≈ 80 kN. Drawing force during hex-bar production: approximately 30-40 kN per square mm of cross-section reduction × area-reduction in mm². Aging shrinkage 0.05 % linear, drawn AF dimensions shrink slightly post-aging; finishing operations should account for this.
A286 Hex Bar Applications by Industry
A286 hex bar is the canonical raw stock for hex-fastener production:
- A286 hex nut manufacture: Cold-drawn hex bar to standard AF dimensions feeds A286 hex nut hot-upsetting and tapping lines. M6-M64 nut production.
- A286 hex-head bolt manufacture: Hex bar feeds A286 hex bolt head formation in cold-heading operations.
- Aerospace 12-point bolt blanks: Hex bar feeds A286 NAS 6603 12-point bolt machining, 12-point geometry milled from hex blank starting form.
- Industrial valve stems: Hex-cross-section A286 bar for high-temperature valve stems where hex section provides positive wrench engagement at the valve-body interface.
- Hex-shafted machine couplings: Custom hex bar for non-fastener applications, gear couplings, pump impeller shafts, drive shafts requiring positive rotational lock.
- Hex-cross-section bushings: Machined hex outer-profile bushings for instrumentation and test-fixture applications where hex section prevents rotation in mating assembly.
Governing Standards & Material Specifications
Every A286 bar product 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 |
| ASTM | B637 | Precipitation-hardenable bar |
| AMS | 5731 | Bar / forging, solution-treated |
| AMS | 5732 | Bar / forging, solution-treated and aged |
| AMS | 5737 | Bar, sol-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 |
A286 Hex Bar vs Alternative Materials
Engineers compare A286 bar against three alternatives: A286 vs Inconel 718, A286 vs 17-4 PH, and A286 vs Waspaloy. See A286 equivalent grades.
How to Specify A286 Hex Bar
A complete a286 hex bar callout should include: material spec, heat-treatment condition, dimensional standard, size, surface finish, marking, inspection certificate. Example callout:
A286 hex bar, AMS 5732, ASTM A453 grade 660 Class A, sol-treated and aged, 24.0 mm AF (M16 mating size), length 3000 mm, cold-drawn finish, ±0.10 mm AF tolerance, straightness ≤ 2 mm/m, EN 10204 3.1.
A286 Hex Bar, Frequently Asked Questions
What is A286 hex bar used for?
A286 hex bar is the canonical raw stock for hex nut, hex-head bolt, and 12-point bolt manufacture. The hex cross-section matches finished-fastener wrench dimensions, eliminating secondary milling. Also used for hex-shafted couplings, valve stems, and custom hex-section machined components.
What's the difference between hex bar and round bar for nut manufacture?
Hex bar already has the wrench across-flats geometry, feeds directly into upsetting and tapping. Round bar requires secondary milling or broaching to form the hex shape, adding cost and lead time. Hex bar is the higher-throughput, lower-cost path.
What across-flats size for an M16 A286 hex nut?
24 mm AF, matches the ISO 272 / DIN 1915 wrench dimension for M16. TorqBolt cold-draws 24.0 ±0.10 mm AF hex bar specifically for M16 nut and hex-bolt manufacture.
What tolerance on A286 hex bar across-flats?
±0.05 mm at 8-13 mm AF, ±0.07 mm at 13-19 mm, ±0.10 mm at 19-30 mm, ±0.15 mm at 30-46 mm, ±0.20 mm at 46-65 mm. Per ISO 272 standard hex profile tolerance.
Is A286 hex bar magnetic?
No. Magnetic permeability < 1.005 verified per ASTM A342. Preserved through cold drawing, sol-treatment, and aging. Compatible with downstream non-magnetic hex nut and hex bolt manufacture.
What's the maximum across-flats size of A286 hex bar?
Standard production: 65 mm AF (matches M48 wrench). Custom-drawing: up to 80 mm AF in hot-rolled and partially-drawn condition for very large-size fastener manufacture.
Can A286 hex bar be supplied solution-treated only (no aging)?
Yes, AMS 5731 / ASTM B637 sol-treated condition is supplied for fastener-makers who prefer to age post-machining. Solution-treated bar is softer (24-28 HRC) and machines more easily; aging done after thread rolling for higher fatigue strength.
Why is across-corners dimension important?
Across-corners is the maximum hex-bar dimension, used for raw-material handling, packaging, and downstream upsetting die selection. AC = AF × 1.155 for a regular hexagon. Critical for tooling clearance, a 24 mm AF bar has 27.7 mm AC.
Can A286 hex bar be NACE MR0175 verified?
Yes, when supplied with hardness ≤ HRC 35 (HV ≤ 327) per NACE MR0175 / ISO 15156-3 for sour-service. Specify on PO; each heat receives Vickers traverse before release.
Why TorqBolt for A286 Hex Bar
Three reasons aerospace and gas-turbine OEMs place a286 hex bar orders with us:
- Vertically integrated supply, VIM-VAR melt sourcing from approved AMS-conforming mills, in-house hot-rolling + cold-drawing + vacuum heat-treatment. No outsourced critical step.
- Aerospace AQMS, AS9100D-certified factory in Mumbai with published quality manual.
- Lead time discipline, 4-6 weeks for ASTM A453 grade 660 standard sizes, 8-12 weeks for custom-drawing aerospace parts.
Over thirty years in fastener manufacture with active ISO 9001:2015, AS9100D, PED, and NORSOK M-650 quality system audits.
Recent A286 Hex Bar Order Patterns
Active hex bar orders cover 13 mm and 17 mm AF cold-drawn for downstream M8/M10 nut production, 24 mm and 30 mm AF for M16/M20 hex bolt and stud bolt manufacture, custom 50 mm AF for valve-stem applications, and aerospace AS9102 first-article 19 mm AF for M12 NAS-spec hex bolt manufacture.
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