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
Incoloy 840 is a nickel-chromium-iron austenitic heat-resistant alloy with titanium and aluminium additions. This datasheet presents the material within the American (ASTM / ASME / UNS) standard system.
Classed as an austenitic stainless steel but distinguished from standard chromium-nickel grades by its higher nickel content, Incoloy 840 contains enough chromium to form and maintain a protective chromium-oxide (Cr₂O₃) scale that gives it markedly better oxidation resistance at high temperature than conventional 18-8 stainless steels such as 304. The titanium and aluminium additions further stabilise the structure and enhance high-temperature performance, and the alloy resists oxidation and corrosion to temperatures approaching 1000 °C. It combines good high-temperature strength with good fabricability and weldability, and is supplied in the annealed condition.
Typical applications include electric heating elements — heating rods, tubes and coils — automotive emission-control systems, industrial furnace parts, and heat exchangers.
| Property | Value | Unit |
|---|---|---|
| Density | 7.90 | g/cm³ |
| Melting range | 1370–1400 | °C |
| Elastic modulus | 197 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 15.0 | µm/m·°C |
| Thermal conductivity (20 °C) | 13.0 | W/m·K |
| Specific heat (20 °C) | 460 | J/kg·K |
| Structure | Austenitic (FCC) | — |
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | Balance | — | Base element |
| Nickel | Ni | 19.0 | 22.0 | Austenite stabiliser; oxidation resistance |
| Chromium | Cr | 19.5 | 21.0 | Cr₂O₃ scale; oxidation resistance |
| Titanium | Ti | 0.15 | 0.60 | Stabiliser; high-temperature performance |
| Aluminium | Al | 0.15 | 0.60 | Stabiliser; oxidation resistance |
| Manganese | Mn | — | 1.00 | Deoxidiser |
| Silicon | Si | — | 1.00 | Oxidation resistance |
| Carbon | C | — | 0.08 | Carbide formation |
Annealed condition, typical values for UNS S33400.
| Condition | Property | Value |
|---|---|---|
| Annealed | Tensile strength (UTS) | 500–880 MPa |
| Annealed | 0.2% yield strength | 210–550 MPa |
| Annealed | Elongation at break | up to 30 % |
| Cold-worked | Tensile strength (UTS) | higher; less ductile |
| — | Elastic modulus | 197 GPa |
Confirm against the mill test report. Properties depend on product form and condition.
| Environment | Performance | Notes |
|---|---|---|
| High-temperature oxidation | Excellent | Cr₂O₃ scale; to about 1000 °C |
| Compared with 304 / 316 | Superior | Higher Ni + Cr for oxidation |
| Sulfates / chlorides / nitrates | Very Good | Good resistance |
| Cyclic high-temperature service | Very Good | Stable protective scale |
| Aqueous / general | Good | Austenitic stainless behaviour |
The high chromium and nickel content gives a stable chromium-oxide scale and oxidation resistance well above that of standard 18-8 stainless steels, making the alloy well suited to high-temperature heating and furnace service.
An austenitic heat-resistant alloy; not hardenable by precipitation. Properties are set by annealing.
Anneal Anneal (solution anneal) at approximately 1010–1120 °C and cool rapidly (air or water quench) to dissolve carbides and restore a uniform austenitic structure. The alloy is not strengthened by heat treatment; cold work raises strength.
Good weldability by the conventional processes for austenitic stainless and nickel alloys; matching or compatible austenitic filler is used. The alloy is readily formed and welded.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Good | Matching / compatible austenitic filler |
| GMAW / MIG | Good | Compatible filler |
| Resistance / spot | Good | — |
Weld with conventional austenitic-stainless practice and clean surfaces; post-weld annealing may be applied where required.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Moderate; work-hardens, rigid setups, sharp tooling |
| Speeds | Slower than carbon steel; positive feeds |
| Coolant | Ample coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Good; work-hardens, anneal between heavy operations |
| Hot forming | Readily formed hot; anneal afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Electric heating | Heating rods, tubes, coils | Oxidation resistance + heat efficiency |
| Automotive | Emission-control system parts | High-temperature oxidation resistance |
| Industrial furnace | Furnace internals and fixtures | High-temperature stability |
| Process / power | Heat exchangers, heaters | Oxidation + corrosion resistance |
| Product Form | ASTM Standard | ASME |
|---|---|---|
| Plate, sheet and strip | ASTM A240 | ASME SA-240 |
| Bar and rod | UNS S33400 | — |
| Tube and pipe | UNS S33400 | — |
| Wire | UNS S33400 | — |
Nickel-chromium-iron austenitic heat-resistant alloy. UNS S33400.
| Alloy | Ni % | Cr % | Type | Best Used For |
|---|---|---|---|---|
| Incoloy 840 | 19–22 | 19.5–21 | Austenitic + Ti/Al | Heating elements, oxidation resistance to ~1000 °C |
| Incoloy 800 | 30–35 | 19–23 | Austenitic Fe-Ni-Cr | General high-temperature oxidation / carburisation |
| Incoloy 800H | 30–35 | 19–23 | Austenitic Fe-Ni-Cr | Higher-temperature creep service |
| Type 310S | 19–22 | 24–26 | Austenitic stainless | High-temperature oxidation resistance |
| Type 304 | 8–10.5 | 18–20 | Austenitic stainless | General-purpose stainless steel |
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