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 Fittings
A286 fittings are precipitation-hardening superalloy pipe fittings — butt-weld elbows, tees, reducers, caps, crosses, laterals — used to direct, branch, or terminate A286 pipe in high-temperature pressure-bearing service. TorqBolt manufactures A286 fittings to ASTM A403 (forged austenitic stainless fittings extended for A286), ASME B16.9 (factory-made buttwelding fittings dimensions), ASME B16.11 (forged socket-weld fittings), and MSS-SP-43 standards. Sizes 1/2 inch through 24 inch NPS in schedules SCH 10S, 40S, 80S, 160. Heat-treated per AMS 5731 / 5732 to deliver 130 ksi tensile / 95 ksi yield, retained mechanical properties to 700 °C. Distinguished from A286 flanges by attachment method (fittings = butt-weld or socket-weld; flanges = bolted face). See parent A286 bar stock, related A286 pipe, A286 flanges, and the canonical chemical composition, A286 welding rod & weldability.
About A286 Fittings
A286 fittings are produced by hot forging from A286 forged bar or plate, then machined to the final ASME B16.9 geometry — typical operations include hot-forming of elbow bends, hot-piercing for tee branches, machining of reducer profiles, and end-bevel preparation for butt-weld attachment. Each fitting is solution-treated 1650-1800 °F and aged 1325 °F × 16 hours per AMS 5732. Pressure-tested per ASTM A403 (3× design pressure) and ultrasonically inspected per ASTM A388. End-bevel angle 37.5° ± 2.5° per ASME B16.9 for butt-weld preparation. Each fitting ships with EN 10204 3.1 mill cert; 3.2 third-party witness available for nuclear, offshore and aerospace applications.
A286 Fitting Types & Standards
TorqBolt produces A286 fittings in five primary configurations:
- Butt-weld elbows (ASME B16.9) — Long-radius (1.5 × NPS) and short-radius (1.0 × NPS) 90° and 45° elbows. Long-radius is the dominant choice for fluid-conveyance to minimize pressure drop.
- Butt-weld tees (ASME B16.9) — Equal tees (branch ⌀ = run ⌀) and reducing tees (branch ⌀ < run ⌀). Used for branch connection in piping systems.
- Butt-weld reducers (ASME B16.9) — Concentric (centerline-aligned) and eccentric (offset, used for liquid-handling lines to allow drainage) reducers. Sizes 1×3/4 to 24×20 inch NPS.
- Butt-weld caps (ASME B16.9) — Pipe-end termination caps — typically dished or hemispherical end. Used for pressure-vessel access port termination and instrumentation pipe stub-out.
- Forged socket-weld fittings (ASME B16.11) — Smaller-size fittings (1/8-2 inch NPS) — socket joint + fillet weld. Used in instrumentation and small-bore process piping.
A286 Fitting Sizes & Pressure Class Reference
| NPS (inch) | Long-radius elbow R | Equal tee branch | Reducer length | Cap length | Pressure class |
|---|---|---|---|---|---|
| 1/2 | 38.1 mm | 38.1 mm | 38.1 mm | 25.4 mm | Schedule |
| 1 | 76.2 mm | 63.5 mm | 50.8 mm | 38.1 mm | Schedule |
| 2 | 152.4 mm | 127 mm | 101.6 mm | 76.2 mm | Schedule |
| 3 | 228.6 mm | 165.1 mm | 127 mm | 101.6 mm | Schedule |
| 4 | 304.8 mm | 203.2 mm | 152.4 mm | 127 mm | Schedule |
| 6 | 457.2 mm | 279.4 mm | 203.2 mm | 152.4 mm | Schedule |
| 8 | 609.6 mm | 381 mm | 254 mm | 203.2 mm | Schedule |
| 12 | 914.4 mm | 508 mm | 355.6 mm | 279.4 mm | Schedule |
A286 Fittings Manufacturing Process
Every a286 fittings TorqBolt ships traces back to a vacuum-induction-melted plus vacuum-arc-remelted (VIM-VAR) ingot meeting AMS 5731 / 5732 chemistry. Process route:
- VIM-VAR forged bar / plate input: AMS 5731 / 5732 chemistry. Forged bar for elbows / tees; plate for reducers and caps.
- Hot forging (sizes ≤ 8 inch NPS): Closed-die forging at 1095-1150 °C — produces near-net-shape elbow bends, tee branches, reducer profiles.
- Hot-pressing (large sizes): Plate hot-formed in mandrel + forming die for large elbows (8-24 inch NPS) — sequential bending operations.
- Machining: 5-axis CNC machines fitting to final ASME B16.9 geometry — interior bore, exterior contour, end-bevel preparation.
- End-bevel preparation: Butt-weld ends machined to 37.5° ± 2.5° bevel angle per ASME B16.9 — critical for downstream field welding.
- Solution treatment: Vacuum or atmosphere furnace 1650 °F (AMS 5737) or 1800 °F (AMS 5732). 1 h per inch of section, oil-quench.
- Precipitation aging: 1325 °F for 16 hours, air-cool. Hardness 29-32 HRC.
- Hydrostatic pressure test: Each fitting tested per ASTM A403 — 3× design pressure for 30 seconds, no leakage. Aerospace and nuclear lots: 4× pressure.
- Ultrasonic test + LPI: 100 % UT per ASTM A388 + LPI per ASTM E1417 — internal flaw + surface defect detection.
A286 Fittings 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:
- Dimensional check per ASME B16.9 — radius, branch ⌀, reducer length, end-bevel angle.
- Wall thickness verified by ultrasonic gauge — typically ≥ 87.5 % of nominal pipe schedule wall.
- Hydrostatic pressure test 100 % per ASTM A403 — 3× design pressure.
- Ultrasonic test 100 % per ASTM A388 — internal flaw detection. Class 1 for aerospace / nuclear.
- LPI per ASTM E1417 on every aerospace lot — Class 1 sensitivity for surface defects.
- Hardness sample 1 per heat per ASTM E384.
- Tensile coupon from each heat per ASTM E8 + elevated-temperature per E21.
- Magnetic permeability < 1.005 per ASTM A342.
- AS9102 first-article on aerospace heats; EN 10204 3.2 third-party witness for nuclear and offshore.
A286 Fittings Installation & Service Practice
Fittings are pressure-bearing flow-direction components — pressure rating per ASTM A403 / ASME B31 calculation using fitting wall thickness and A286 yield stress at temperature. For an 8 inch NPS SCH 80S A286 elbow at 700 °C: max design pressure ≈ 50 bar. Thermal expansion: A286 coefficient 17.0 µm/m·°C — long pipe runs with elbow turns require expansion loops or bellows to absorb thermal strain. Field welding: use matching A286 welding rod per AMS 5853, post-weld solution-treat + age for full-strength weld zone. For repeat pressure-cycling service, fatigue analysis per ASME B31.3 required.
A286 Fitting Applications by Industry
A286 fittings serve high-temperature pressure-bearing piping systems:
- Jet-engine bleed-air ducting: Aerospace A286 elbows + tees on jet-engine bleed-air ducts, anti-ice supply lines, environmental-control distribution. A286 jet engine fasteners ecosystem.
- Industrial gas turbine fuel manifold: A286 elbows + tees on combustor fuel-distribution manifolds, ignition pilot lines. A286 gas turbine applications.
- Petrochemical hydrogen-service piping: A286 elbows / tees / reducers on refinery hydrogen-service process lines — HTHA-resistant at 540-700 °C operating temperatures.
- Oil & gas downhole completion strings: A286 elbows / reducers on sour-service downhole completion strings. NACE MR0175 sour-service compliant when hardness ≤ HRC 35.
- Cryogenic LNG transfer system: A286 elbows / tees on LNG storage-vessel transfer piping + hydrogen-storage manifold piping. Retains 85 % toughness at -196 °C.
- Nuclear reactor internal piping: ASTM A453 grade 660 / ASME III A286 fittings for nuclear reactor instrumentation tubing, control-rod-drive housing penetrations. A286 nuclear applications.
Governing Standards & Material Specifications
Every A286 product is released against the applicable industry standard. EN 10204 type 3.1 mill certificates ship with every order. See A286 AMS / ASTM specifications hub.
| Authority | Specification | Coverage |
|---|---|---|
| ASTM | A453 grade 660 Cl. A/B/C/D | High-temperature bolting material |
| ASTM | A638 grade 660 Type 1/2 | Forged stock |
| AMS | 5731 | Bar / forging — solution-treated |
| AMS | 5732 | Bar / forging — solution-treated and aged |
| 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 Fittings vs Alternative Materials
Engineers compare A286 against three alternatives: A286 vs Inconel 718, A286 vs 17-4 PH, and A286 vs Waspaloy. See A286 equivalent grades.
How to Specify A286 Fittings
A complete a286 fittings callout should include all relevant elements. Example callout:
A286 fitting, ASTM A403 grade A286, ASTM A453 grade 660 chemistry, sol-treated and aged, 90° long-radius elbow, NPS 4 inch × SCH 80S, butt-weld ends with 37.5° bevel, hydrostatic pressure tested, EN 10204 3.1, ultrasonic tested per ASTM A388.
A286 Fittings — Frequently Asked Questions
What ASTM standard covers A286 pipe fittings?
ASTM A403 — covers seamless and welded austenitic stainless steel fittings extended for A286 chemistry. ASME B16.9 defines factory-made buttwelding fittings dimensions; ASME B16.11 covers forged socket-weld fittings. Reference ASTM A453 grade 660 for material chemistry.
What's the difference between long-radius and short-radius A286 elbow?
Long-radius: bend radius = 1.5 × nominal pipe size (NPS) — preferred for fluid-conveyance to minimize pressure drop. Short-radius: bend radius = 1.0 × NPS — used where space is limited (engine compartments, equipment cabinets). LR is the dominant ~90 % of orders.
Can A286 fittings be welded in field?
Yes — TIG / GTAW with matching A286 welding rod (AMS 5853). Pre-heat NOT required for thicknesses ≤ 50 mm. Post-weld solution-treatment + aging required for full-strength weld zone (1650 °F sol → quench → 1325 °F aging × 16 h).
What pressure class are A286 fittings rated for?
Schedule-rated per ASME B36.19M — pressure rating depends on size, schedule (wall thickness), and service temperature. For 4 inch NPS SCH 80S A286 fitting at 700 °C: ~50 bar. ASTM A403 pressure-test 3× design pressure on every fitting confirms compliance.
What's the smallest A286 fitting size?
1/8 inch NPS (10.3 mm OD) for socket-weld fittings per ASME B16.11. 1/2 inch NPS (21.3 mm OD) for butt-weld fittings per ASME B16.9. Below 1/2 inch use A286 tube with compression fittings.
Are A286 fittings magnetic?
No. Magnetic permeability < 1.005 verified per ASTM A342. Critical for instrumentation piping and sensitive aerospace bleed-air systems where adjacent magnetic material would cause EMI.
Are A286 fittings NACE MR0175 sour-service compliant?
Yes — when supplied with hardness ≤ HRC 35 per NACE MR0175 / ISO 15156-3. Specify on PO; each heat receives Vickers traverse before release for sour-service oilfield applications.
What surface finish on A286 fittings?
Pickled-and-passivated per ASTM A967 Type II — bright surface free of oxide and scale. Aerospace lots: additional silver / nickel anti-galling coat at end-bevel for above-540 °C service.
What's the lead time on A286 fittings?
Standard sizes 1/2-4 inch NPS: 8-12 weeks from heat release. Larger sizes 6-12 inch NPS: 12-16 weeks. Custom 14-24 inch NPS: 14-20 weeks. Aerospace AS9102 first-article + EN 10204 3.2: add 2-3 weeks.
Why TorqBolt for A286 Fittings
Three reasons aerospace and industrial OEMs place a286 fittings orders with us:
- Vertically integrated supply — VIM-VAR melt sourcing, in-house forging + machining + vacuum heat-treatment.
- 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 manufacture with active ISO 9001:2015, AS9100D, PED, and NORSOK M-650 quality system audits.
Recent A286 Fittings Order Patterns
Active A286 fitting orders cover 1-2 inch NPS SCH 80S elbows + tees for jet-engine bleed-air ducting, 4-6 inch NPS SCH 40S long-radius elbows for industrial gas-turbine combustor manifold, custom 8-12 inch NPS reducers for petrochemical hydrogen-service refinery, and ASME III certified 2-4 inch NPS elbows + tees for nuclear pressure-vessel internal piping.
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