Physical properties
| Density | 8.23 | g/cm³ |
Informative values: they vary with composition, condition and test method. Use the governing standard or measured mill data for pressure and heat-transfer calculations.
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 % | |
|---|---|---|---|
| Fe | Iron | Bal. | |
| Cr | Chromium | 21 – 23% | |
| Ni | Nickel | 19 – 22.5% | |
| Co | Cobalt | 16 – 21% | |
| Mo | Molybdenum | 2.5 – 4% | |
| W | Tungsten | 2 – 3.5% | |
| Mn | Manganese | 0.5 – 2% | |
| C | Carbon | 0.05 – 0.15% | |
| Si | Silicon | 0.2 – 0.8% | |
| Ta | Tantalum | 0.3 – 1.25% | |
| N | Nitrogen | 0.1 – 0.3% | |
| Al | Aluminium | 0.1 – 0.5% |
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 ≥ % | Other requirements and notes |
|---|---|---|---|---|---|
| Bar and forgings | |||||
| Bar and rod | Solution annealed at ≥1150 °C, rapidly cooled | ≥ 690 (100 ksi) | ≥ 310 (45 ksi) | ≥ 40 | |
| Plate, sheet and strip | |||||
| Plate, sheet and strip | Annealed and descaled | ≥ 690 (100 ksi) | ≥ 310 (45 ksi) | ≥ 40 | |
| Tube and pipe | |||||
| Seamless pipe and tube | Solution annealed and descaled | ≥ 690 (100 ksi) | ≥ 310 (45 ksi) | ≥ 40 | |
| Welded pipe and tube | Solution annealed | ≥ 690 (100 ksi) | ≥ 310 (45 ksi) | ≥ 40 | |
| Fittings and flanges | |||||
| Fittings (factory-made wrought butt-weld / socket) | 2150 °F [1177 °C] minimum, rapid air or water quench | — | — | — | Tensile properties follow the starting material. No tension test on the finished fitting unless agreed. Minimum temperature. |
Grain size
Required by the standard, conditionally — t ≤3.175 mm: ASTM micrograin size No. 3.0 or finer (mean grain dia. 0.127 mm); t >3.175 mm: No. 1.5 or finer (0.214 mm)
Applies to annealed sheet and strip only, banded by thickness; it does not apply to bar — for bar, grain size is specified only for N12160, so Haynes 556 bar carries no grain-size acceptance requirement.
More detail 2
The direction is the reverse of 800H/800HT: here the limit is "No. 3.0 or finer", a floor on the fine side (thin sheet needs fine grain to form), whereas N08810 requires "No. 5 or coarser", a ceiling on the fine side (creep needs coarse grain).
Whenever you see "ASTM grain size number N", check first whether it reads "or finer" or "or coarser".
Where this grade is recommended
Matched in 3 service conditions; ranks and scores computed from the condition-scoring matrix.
| Service condition | Industry | Temperature | Rank | Score |
|---|---|---|---|---|
| Waste-to-energy boilers | Environmental & FGD | 850 – 1000 °C | 1 / 8 | 90 |
| Furnace internals & fixtures | Furnaces & Vacuum | 900 – 1150 °C | 5 / 12 | 86 |
| Gas-turbine hot section | Power & Nuclear | 950 – 1150 °C | 5 / 10 | 82 |
Designations & equivalents
| W.Nr. (Germany) | 1.4883 |
| EN designation | X10CrNiCoMoN 22-20-18 |
| Trade name(s) | Haynes 556 |
| ASTM / AISI | B366 / B435 / B472 / B572 / B619 / B622 |
| AMS (SAE aerospace) | 5831 / 5874 / 5877 |
| AWS (welding) | A5.9 ER3556 |
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
9 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 Haynes 556 · UNS R30556?
Haynes 556 · UNS R30556 — Fe-Ni superalloys. Sulphidation- and multi-mode-corrosion resistant — the benchmark for waste-to-energy boilers
What is the maximum service temperature of R30556?
Typically about 1100 °C; the practical limit depends on media, stress and design life — acceptance per the governing standard.
What is the tensile strength of R30556?
The specified minimum tensile strength is 690 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 R30556?
ASTM B366, ASTM B435, ASTM B472, ASTM B572, ASTM B619, ASTM B622, AMS 5831, AMS 5874, AMS 5877
Where is R30556 typically used?
Waste-to-energy boilers (Environmental & FGD); Furnace internals & fixtures (Furnaces & Vacuum); Gas-turbine hot section (Power & Nuclear)
In which forms is R30556 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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