Chemical composition
Nominal: mid-range where both limits are given, the cap where only a maximum is, balance takes the remainder. Exact specified ranges below.
| Element | Name | Content % | |
|---|---|---|---|
| Main elements7 elements | |||
| Fe | Iron | Bal. | |
| Ni | Nickel | 24 – 27% | |
| Cr | Chromium | 13.5 – 16% | |
| Ti | Titanium | 1.9 – 2.35% | |
| Mo | Molybdenum | 1 – 1.5% | |
| V | Vanadium | 0.1 – 0.5% | |
| B | Boron | 0.001 – 0.01% | |
| Element | Name | Content % | |
|---|---|---|---|
| Minor & residual5 elements | |||
| Al | Aluminium | ≤ 0.35% | |
| C | Carbon | ≤ 0.08% | |
| Mn | Manganese | ≤ 2% | |
| Si | Silicon | ≤ 1% | |
| P | Phosphorus | ≤ 0.04% | |
Mechanical minima by form
Guaranteed values differ by form, size and delivery condition; quotations confirm the specification, form, size and condition.
| Form | Condition | Rm MPa | Rp0.2 MPa | A ≥ % |
|---|---|---|---|---|
| Bar and forgings | ||||
| Bar, forgings and forging stock | Grade 660 Type 1: solution treated at 900 ± 15 °C for 2 h, oil or water quenched, aged at 705–760 °C for 16 h | ≥ 895 (130 ksi) | ≥ 585 (85 ksi) | ≥ 15 |
| Bar, forgings and forging stock | Grade 660 Type 2: solution treated at 980 ± 15 °C for 1 h, oil or water quenched, aged at 705–760 °C for 16 h | ≥ 895 (130 ksi) | ≥ 585 (85 ksi) | ≥ 15 |
| Bar and forgings | Hot finished or solution treated only under A638, not yet precipitation hardened | — | — | — |
| Several forms | ||||
| Long products d ≤160 mm and flat products ≥3 mm (EN 10302, 1.4980) | +P (precipitation hardened) | 900 – 1150 | ≥ 600 | ≥ 15 |
| Other | ||||
| Bolts, studs and nuts | A453 Grade 660 Class A/B/C: solution treatment and ageing per the applicable class | ≥ 895 (130 ksi) | ≥ 585 (85 ksi) | ≥ 15 |
| Bolts, studs and nuts (≤63.5 mm) | A453 Grade 660 Class D: solution treated and aged, with an optional second age at 649 °C | ≥ 895 (130 ksi) | ≥ 725 (105 ksi) | ≥ 15 |
| Bolts, studs and nuts (>63.5 mm) | A453 Grade 660 Class D: solution treated and aged, with an optional second age at 649 °C | ≥ 825 (120 ksi) | ≥ 655 (95 ksi) | ≥ 15 |
Hardness requirement
Required by the standard — 248 – 341 HBW (24 – 37 HRC)
A mandatory acceptance requirement alongside tensile ≥895 MPa, yield ≥585 MPa and elongation ≥15%.
More detail 1
Class D carries a narrower hardness band (248–321 HBW / 24–35 HRC) and a higher yield requirement.
Stress-rupture requirement
| Heat treatment | Grade 660 Class A / B / C |
| Test temperature | 1200 °F (649 °C) |
| Test stress | 56 ksi (385 MPa) |
| Minimum life | ≥ 100 h |
Class D is specified separately.
More detail 1
Grade 660 is used for high-temperature bolting; Grade 660 is UNS S66286 (A-286).
This is a pass/fail acceptance test, not a design creep curve.
Where this grade is recommended
Matched in 6 service conditions; ranks and scores computed from the condition-scoring matrix.
| Service condition | Industry | Temperature | Rank | Score |
|---|---|---|---|---|
| HT fasteners & springs | Power & Nuclear | 400 – 650 °C | 1 / 7 | 92 |
| High-pressure hydrogen | Hydrogen & New Energy | ≤ 80 °C | 1 / 4 | 90 |
| HT bolting & seal rings | Aerospace | 400 – 650 °C | 2 / 6 | 90 |
| HS fasteners & shafts | Aerospace | 300 – 650 °C | 3 / 9 | 90 |
| Turbo & hot fasteners | Automotive & Racing | 600 – 850 °C | 3 / 4 | 88 |
| Hydroprocessing & refinery hot service | Oil & Gas | 250 – 400 °C | 8 / 8 | 82 |
Designations & equivalents
| W.Nr. (Germany) | 1.4980 |
| EN designation | X6NiCrTiMoVB25-15-2 |
| Trade name(s) | A-286 / Pyromet A-286 |
| ASTM / AISI | A453 / A638 |
| AMS (SAE aerospace) | 5525 / 5726 / 5731 / 5732 / 5734 / 5737 / 5804 / 5895 |
| JIS (Japan) | SUH660 |
Cross-references are common near-equivalents for search and shortlisting; substitution across standards requires clause-by-clause verification. All grades in one cross-reference table →
Applicable standards
11 specifications. Name the standard and its edition on the order.
Guaranteed values and required tests differ between specifications — see Mechanical minima by form for the figures per form.
Frequently asked questions
What is A-286 (GH2132) · UNS S66286?
A-286 (GH2132) · UNS S66286 — Fe-Ni superalloys. Iron-nickel age-hardened alloy — fasteners and turbine discs to 650 °C
What is the maximum service temperature of S66286?
Typically about 650 °C; the practical limit depends on media, stress and design life — acceptance per the governing standard.
What is the tensile strength of S66286?
The specified minimum tensile strength is 895 MPa for the main product form. Minima for other forms and sizes are listed under "Mechanical minima by form" on this page.
Which standards cover S66286?
ASTM A638/A638M, ASTM A453/A453M, AMS 5525, AMS 5726, AMS 5731, AMS 5732, AMS 5734, AMS 5737, AMS 5804, AMS 5895, EN 10302 (creep-resisting steels, nickel and cobalt alloys)
Where is S66286 typically used?
HT fasteners & springs (Power & Nuclear); High-pressure hydrogen (Hydrogen & New Energy); HT bolting & seal rings (Aerospace); HS fasteners & shafts (Aerospace)
In which forms is S66286 available?
Tube, plate, strip, bar, forgings, wire and other forms — sizes and delivery condition confirmed per order, with EN 10204 3.1 / 3.2 certification.
Same series
Download PDF datasheet
This grade’s datasheet as an A4 PDF — for filing, printing or forwarding to colleagues.
Download PDF datasheetSupply & enquiry
Tube & pipeφ1 – 219 × 0.25 – 25 mm
Plate4.76 – 80 mm
Barφ8 – 300 mm
Wire & filler metalsφ0.01 – 8 mmFor this grade we can supply, against your service conditions:
- Tube, plate, strip, bar, forgings, wire and more — with size range and lead time
- Chemistry and mechanical test report (EN 10204 3.1 / 3.2)
- Like-for-like alternatives and selection advice
- Applicable standards and inspection scope
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