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 Square Bar
A286 square bar is square-cross-section A286 bar stock used for shaft keys, machined brackets, fixtures, and custom machined components requiring 90°-corner geometry. TorqBolt manufactures A286 square bar to AMS 5731, AMS 5732, ASTM A453 grade 660, and ASTM B637 standards in 5-100 mm sizes. Hot-rolled or cold-drawn finishes; ±0.10-0.30 mm tolerance per side depending on size and finish. Heat-treated to deliver 130 ksi tensile / 95 ksi yield, retained mechanical properties at 700 °C continuous service. See parent A286 bar stock, sister variants A286 round bar, hex bar, flat bar, and the canonical chemical composition + A286 mechanical-property data.
About A286 Square Bar
A286 square bar is produced by hot-rolling A286 ingot through a square-pass roll mill, or by cold-drawing hot-rolled bar through a square die for tighter tolerance. Standard sizes 5-100 mm per side; tolerances range from ±0.30 mm hot-rolled to ±0.10 mm cold-drawn. Square bar is the canonical raw stock for shaft keys per ISO 2491 / DIN 6885 (parallel keys) — A286 keys are used in high-temperature shaft couplings, gas-turbine accessory drives, and aerospace gearbox shafting where standard 4140 carbon-steel keys would lose strength above 425 °C. Square bar also feeds custom machined brackets, fixtures, and aerospace structural components requiring 90° corners. Each lot is solution-treated and aged per AMS 5732, surface-pickled, and ships with EN 10204 3.1 mill cert.
A286 Square Bar Production Conditions & Standards
TorqBolt produces A286 square bar in three primary production conditions:
- Hot-rolled solution-treated (AMS 5731 / ASTM B637) — Hot-rolled in a square-pass mill at 1095-1150 °C, sol-treated 1800 °F + oil quench. Hardness 24-28 HRC. Tolerance ±0.30 mm. Used as raw stock for downstream aging.
- Hot-rolled solution-treated and aged (AMS 5732) — Hot-rolled, sol-treated 1650 °F + aged 1325 °F × 16 h. Hardness 29-32 HRC. Tolerance ±0.30 mm. The default mill-aged square bar.
- Cold-drawn precision (custom) — Cold-drawn through a square die for tighter ±0.10 mm tolerance and improved surface finish (Ra ≤ 2 µm). Used for precision shaft keys and aerospace structural components.
- Hot-rolled + machined (custom) — Hot-rolled over-size square bar machined to final dimension via milling or shaping — used when intermediate sizes outside standard rolling tolerances are required.
- ASTM B637 wrought + sol-treated — ASTM B637 cover for non-aerospace precipitation-hardenable bar — equivalent to AMS 5731 sol-treated condition for industrial high-temperature service.
A286 Square Bar Sizes & Tolerance Reference
| Side dimension | Hot-rolled tolerance | Cold-drawn tolerance | Standard length | Available specs |
|---|---|---|---|---|
| 5-10 mm | ±0.30 mm | ±0.10 mm | 3-6 m | AMS 5731 / 5732 / B637 |
| 12-16 mm | ±0.30 mm | ±0.13 mm | 3-6 m | AMS 5731 / 5732 / B637 |
| 18-25 mm | ±0.40 mm | ±0.15 mm | 3-6 m | AMS 5731 / 5732 / B637 |
| 30-40 mm | ±0.50 mm | ±0.20 mm | 3-6 m | AMS 5731 / 5732 / B637 |
| 50-65 mm | ±0.60 mm | ±0.25 mm | 3 m | AMS 5731 / 5732 / B637 |
| 75-100 mm | ±0.80 mm | — | 3 m | AMS 5731 / B637 |
A286 Square Bar Manufacturing Process
Every a286 square 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 ingot input: Vacuum-induction-melted + vacuum-arc-remelted ingot to AMS 5731 / 5732 chemistry. Element ranges per ASTM A453 grade 660.
- Cogging + reheat: Ingot broken down to billet at 1095 °C; reheated to 1150 °C for square-rolling pass.
- Square-pass hot rolling: Billet rolled through alternating square-edge rolls — typical reduction 4:1 from billet to bar. Sizing pass for final dimensions.
- Pickling: Hot-rolled square bar pickled in HNO₃ + HF to remove mill scale. Surface inspected per ASTM E45.
- Cold drawing (precision lots): For ±0.10 mm tolerance, hot-rolled bar cold-drawn through a square die at 0.5 m/min. Single-pass for sides ≤ 25 mm.
- Solution treatment: Vacuum or atmosphere furnace 1650 °F (AMS 5737 / 5732) or 1800 °F (AMS 5731). 1 hour per inch, oil-quench.
- Precipitation aging: 1325 °F for 16 hours, air-cool. Hardness 29-32 HRC for AMS 5732.
- Straightening: Multi-roll straightener for ≤ 2 mm/m straightness tolerance.
- Cut to length + label: Bar cut to drawing length on band saw, end-faced, heat-traceability labelled.
A286 Square 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:
- Side dimension verified by snap gauge or laser micrometer per AMS 5731 / 5732 tolerance.
- Squareness check by 90° gauge — corner deviation per drawing.
- Straightness check per ASTM A484 — typical ≤ 2 mm/m for cold-drawn, ≤ 3 mm/m for hot-rolled.
- Surface inspection 100 % visual for laps, seams, scale per ASTM E45.
- Hardness sample 1 per heat per ASTM E384 — 4-point Vickers.
- 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 Square Bar Downstream Forming & Machining
Square bar is raw stock — torque does not apply directly. Downstream applications: parallel-key shear stress in service follows ISO 2491 / DIN 6885 — for an A286 8 × 7 mm key in a 35 mm shaft, recommended max shear torque is ~150 N·m at room temperature, dropping to ~110 N·m at 700 °C. Aging shrinkage 0.05 % linear; design machining allowance accordingly. For high-vibration applications, use square key + set-screw retention to prevent key migration.
A286 Square Bar Applications by Industry
A286 square bar serves shaft-key, structural, and machined-component applications:
- Aerospace shaft key manufacture: A286 square bar machined to ISO 2491 / DIN 6885 parallel keys for jet-engine accessory drive shafts, helicopter transmission, and gas-turbine compressor shafting. Retains key shear-strength at 700 °C.
- Industrial gas turbine drive coupling: Square bar machined to gear-coupling key stock for Siemens / GE / Mitsubishi gas-turbine accessory drives. A286 gas turbine applications.
- Aerospace structural brackets: Square bar machined to mounting brackets, support fittings, gimbal pivot blocks for aerospace fuel-system, hydraulic-actuator, and engine-accessory hardware.
- Test-fixture & tooling stock: Square bar as raw stock for high-temperature test fixtures, gas-turbine combustor liner alignment fixtures, and aerospace assembly tooling.
- Defence airframe structural: Custom-machined square bar for fighter-jet gun mounts, missile-launcher attach blocks, structural reinforcement gussets.
- Pressure-vessel structural reinforcement: Square bar for ASME Section III nuclear pressure-vessel structural reinforcement, control-rod-drive housing supports. A286 nuclear applications.
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 Square 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 Square Bar
A complete a286 square bar callout should include: material spec, heat-treatment condition, dimensional standard, size, surface finish, marking, inspection certificate. Example callout:
A286 square bar, AMS 5732, ASTM A453 grade 660 Class A, sol-treated and aged, 16.0 mm × 16.0 mm cross-section, length 3000 mm, cold-drawn finish, ±0.13 mm tolerance per side, straightness ≤ 2 mm/m, EN 10204 3.1.
A286 Square Bar — Frequently Asked Questions
What is A286 square bar used for?
Square bar is the canonical raw stock for shaft keys (per ISO 2491 / DIN 6885), machined brackets, fixtures, support blocks, and custom 90°-corner machined components. A286 square bar specifically serves high-temperature applications above 425 °C where carbon-steel keys lose strength.
What's the standard side-dimension tolerance on A286 square bar?
Hot-rolled: ±0.30-0.80 mm depending on size. Cold-drawn: ±0.10-0.25 mm. Cold-drawn provides 3-4× tighter tolerance and is required for precision shaft-key applications.
Can A286 square bar be supplied in stock 6-meter lengths?
Yes — hot-rolled and cold-drawn 6 m standard length for sizes 5-50 mm. Sizes 50-100 mm typically supplied in 3 m lengths due to handling and straightness considerations.
Is A286 square bar magnetic?
No. Magnetic permeability < 1.005 verified per ASTM A342 — preserved through hot rolling, cold drawing, sol-treatment, and aging. Compatible with non-magnetic shaft assembly, instrumentation, and aerospace electromagnetic-sensitive structural applications.
What's the maximum size of A286 square bar?
Standard production: 100 × 100 mm (4 × 4 inch). Custom-drawing: up to 150 × 150 mm in hot-rolled condition. Sizes above 100 mm typically use A286 forged bar instead.
Can A286 square bar replace 4140 keys?
For service > 425 °C — yes. A286 retains shear strength at 700 °C where 4140 carbon-steel keys lose strength above 425 °C. For ambient-temperature applications 4140 is more cost-effective; use A286 only when temperature, magnetic, or corrosion requirements justify the 5-8× cost premium.
What surface finish on A286 square bar?
Hot-rolled: pickled finish, Ra ~6-12 µm. Cold-drawn: Ra ~1-3 µm. For aerospace structural lots: passivated per ASTM A967 Type II for corrosion resistance.
Are corners sharp or radiused on A286 square bar?
Hot-rolled: radiused corners (R ≈ 0.5-1.5 mm depending on size). Cold-drawn: sharper corners (R ≈ 0.2-0.5 mm). For sharp 90° corners, specify cold-drawn + corner-grinding finish per drawing.
What's the lead time on AMS 5732 cold-drawn A286 square bar?
Standard sizes 5-50 mm: 4-6 weeks from heat release. Larger sizes 50-100 mm: 6-10 weeks (limited mill availability). Aerospace AS9102 first-article: add 1-2 weeks.
Why TorqBolt for A286 Square Bar
Three reasons aerospace and gas-turbine OEMs place a286 square 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.
30+ years of fastener-manufacturing track record. Active certifications: ISO 9001:2015, AS9100D AQMS, PED 2014/68/EU and NORSOK M-650 QTR.
Recent A286 Square Bar Order Patterns
Active square bar orders cover 8 × 8 mm and 10 × 10 mm cold-drawn for ISO 2491 parallel-key manufacture, 25 × 25 mm hot-rolled for aerospace bracket machining, custom 75 × 75 mm hot-rolled for nuclear pressure-vessel structural support, and AMS 5732 16 × 16 mm aerospace AS9102 first-article aerospace gearbox key stock.
Satisfaction Survey
