Bar and Rod
Plate and Sheet
Strip
Pipe and Tube
Wire
Welding
Powder Material
Cast Products
Forged Products
Fittings
Fastening
Round Bar:
φ2–500 mm, 1–6 m length
Flat/Square Bar:
4–100 mm thickness/width
Hex Bar:
A/F 3–100 mm
Hollow Bar:
OD 20–300 mm
Sheet:
0.3–6 mm thickness
Medium Plate:
6–25 mm thickness
Heavy Plate:
25–100 mm thickness
Standard Strip:
0.05–3 mm thick,
10–600 mm wide
Precision strip:
0.01–0.5 mm thick,
tight tolerance ±0.005 mm
Foil:
0.005–0.1 mm thick
Seamless Tube:
OD 6–450 mm,
WT 1–50 mm,
1–12 m length
Welded Tube:
OD 10–600 mm,
WT 1–20 mm
Capillary Tube:
OD 1–10 mm,
WT 0.1–2 mm
Wire Form:
Cold Drawn Wire,
Bright Wire,
Spring Wire,
Fine Wire,
Ultra-fine Wire
General Diameter:
φ0.1–10 mm
Coil Weight:
50–500 kg,
customizable tolerance
Solid Wire:
φ0.8–4.0 mm
Flux-cored Wire:
φ1.2–4.0 mm
Welding Rod:
φ2.0–5.0 mm
Powder Form:
AM 3D Printing Powder,
Spherical Powder,
Gas-atomized Powder,
Water-atomized Powder
Particle Size:
10–150 μm
Sphericity:
≥90% for AM grade
Cast Ingot:
φ200–800 mm
Precision Casting:
min wall 0.5 mm
Cast Pipe:
OD 100–600 mm,
WT 10–50 mm
Forged Bar:
Φ35–500 mm
Forged Ring:
OD 200–2000 mm
Forging Weight:
1–5000 kg
Fittings Form:
Elbow, Tee, Reducer, Flange, Cap, Outlet, Lap Joint
Size range:
1/2''–24'' (DN15–DN600)
Wall thickness:
Sch10–Sch160, STD, XS, XXS
Pressure Class:
150–2500 LB
Fastening Form:
Bolt, Nut, Screw, Stud, Washer, Pin, Rivet
Metric: M3–M64
Imperial: #4–2.5''
Length: 6–500 mm
Alloy 556 is an iron-nickel-chromium-cobalt multipurpose high-temperature alloy. This datasheet presents the material within the American (ASTM / ASME / UNS) standard system.
An iron-nickel-chromium-cobalt alloy, Alloy 556 combines effective resistance to sulfidizing, carburizing and chlorine-bearing environments at high temperature with good oxidation resistance, fabricability and excellent high-temperature strength. It has also been found to resist corrosion by molten chloride and other salts and by molten zinc. Small additions of lanthanum and tantalum contribute to its oxidation resistance and stability. With excellent forming and welding characteristics, it may be forged or hot-worked when brought fully to about 1175 °C (2150 °F), and its good ductility allows cold forming. It is supplied in the solution-annealed condition.
Typical applications include waste-incineration equipment, chemical- and petrochemical-process hardware, industrial-furnace components, and gas-turbine parts exposed to aggressive high-temperature environments.
| Property | Value | Unit |
|---|---|---|
| Density | 8.23 | g/cm³ |
| Melting range | 1240–1345 | °C |
| Elastic modulus | 205 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 14.2 | µm/m·°C |
| Thermal conductivity (20 °C) | 11.0 | W/m·K |
| Specific heat (20 °C) | 431 | J/kg·K |
| Structure | Austenitic (FCC) | — |
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | Balance | — | Base element |
| Nickel | Ni | 19.0 | 22.5 | Austenite stabiliser; thermal stability |
| Chromium | Cr | 21.0 | 23.0 | Oxidation / sulfidation resistance |
| Cobalt | Co | 16.0 | 21.0 | Hot strength; thermal-fatigue resistance |
| Molybdenum | Mo | 2.50 | 4.00 | Solid-solution strengthening |
| Tungsten | W | 2.00 | 3.50 | Solid-solution strengthening |
| Tantalum | Ta | 0.30 | 0.90 | Stabiliser; strength |
| Nitrogen | N | — | 0.30 | Strengthening |
| Manganese | Mn | — | 1.50 | Deoxidiser |
| Lanthanum | La | 0.005 | 0.10 | Oxide-scale adhesion |
| Carbon | C | — | 0.15 | Carbide formation |
Solution-annealed condition, typical values for UNS R30556.
| Condition | Property | Value |
|---|---|---|
| Solution annealed | Tensile strength (UTS) | ≥815 MPa (118 ksi) |
| Solution annealed | 0.2% yield strength | ≥410 MPa (60 ksi) |
| Solution annealed | Elongation at break | ≥40 % |
| At elevated temperature | High-temperature strength | Excellent; creep-resistant |
| — | Elastic modulus | 205 GPa |
Confirm against the mill test report. The alloy combines excellent high-temperature strength with good ductility and long-term stability.
| Environment | Performance | Notes |
|---|---|---|
| Sulfidation | Excellent | Key strength of the alloy |
| Carburisation | Excellent | High chromium + nickel |
| Chlorine-bearing environments | Excellent | High-temperature resistance |
| Oxidation | Good | Lanthanum-stabilised scale |
| Molten chloride salts / molten zinc | Excellent | Resistant to salt and zinc attack |
The balanced iron-nickel-chromium-cobalt composition, with tungsten, molybdenum, tantalum and lanthanum, gives an exceptional combination of resistance to sulfidizing, carburizing and chlorine-bearing environments together with good oxidation resistance and resistance to molten salts and molten zinc.
A single-phase solid-solution alloy; not hardenable by precipitation. Properties are set by solution annealing.
Solution Anneal Solution anneal at approximately 1175 °C (2150 °F) and rapidly cool (water or rapid air cool) to retain the best balance of properties. The alloy is not strengthened by heat treatment; all hot- or cold-worked parts should be annealed and rapidly cooled.
Excellent weldability; readily welded by gas-tungsten-arc, gas-metal-arc, shielded-metal-arc and resistance welding with matching filler. Submerged-arc welding is not recommended (high heat input and slow cooling promote cracking). Avoid contact with copper or copper-bearing materials in the joint area.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Excellent | Matching 556 filler |
| GMAW / MIG | Good | Matching filler |
| SMAW / stick | Good | Matching electrode |
Weld with matching filler and clean surfaces; submerged-arc welding is not recommended.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Difficult; work-hardens, rigid setups, sharp tooling |
| Speeds | Slow speeds, positive feeds, no dwelling |
| Coolant | Ample coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Good ductility; work-hardens, anneal between heavy operations |
| Hot forming | ~1175 °C (held to temperature); anneal and rapid-cool afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Waste incineration | Furnace and grate components | Sulfidation + chlorine resistance |
| Chemical / petrochemical | Reactors, ducting, hardware | Carburisation + corrosion resistance |
| Industrial furnaces | Muffles, baffles, fixtures | High-temperature strength |
| Gas turbine | Combustion / exhaust components | Oxidation + sulfidation resistance |
| Product Form | ASTM Standard | AMS / ASME |
|---|---|---|
| Plate, sheet and strip | ASTM B435 | AMS 5874 · ASME CC2292 |
| Bar and forgings | ASTM B572 | AMS 5874 |
| Seamless pipe and tube | ASTM B622 | ASME SB-622 |
| Welded pipe and tube | ASTM B619 | ASME SB-619 |
Iron-nickel-chromium-cobalt multipurpose high-temperature alloy. UNS R30556.
| Alloy | Cr % | Co % | Ni % | Best Used For |
|---|---|---|---|---|
| Alloy 556 | 21–23 | 16–21 | 19–22.5 | Fe-Ni-Cr-Co multipurpose; sulfidation, carburisation, chlorine, molten salts |
| Alloy 230 | 20–24 | ≤5 | balance | High-temperature strength + oxidation |
| Alloy X | 20.5–23 | 0.5–2.5 | balance | Gas-turbine combustors, furnace parts |
| Alloy 188 | 20–24 | balance | 20–24 | Cobalt-base high-temperature oxidation |
| Alloy 800H | 19–23 | — | 30–35 | General high-temperature service |
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