1.What is Incoloy 840 Tube for tubular heater?
Incoloy 840 tube is premium sheath tubing dedicated to tubular heaters. It boasts superior high-temperature anti-oxidation capability and great heat cycling resistance, ideal for electric heating elements running under long-term high heat. Supports bending, welding and custom dimensional requirements, widely used for oven heaters, air tubular heaters and industrial heating equipment.
2.Material Properties of High-Nickel Alloy Incoloy 840 Tube
| Performance Item | Description |
| Max Continuous Working Temperature | Up to 1038°C,suitable for medium-high temp tubular heater |
| High-Temperature Oxidation Resistance | Forms compact oxide layer, anti-scaling & anti-ablation |
| Thermal Fatigue Resistance | Adapt to frequent heating-cooling cycles, prevent tube cracking |
| Fabrication Performance | Bendable, flareable, shrinkable and weldable for heater production |
| Corrosion & Carburization Resistance | Stable service in dry air, oven and low-corrosion heating environment |
| Cost Advantage | Higher performance than stainless steel, more economical than Incoloy 800 / Inconel 600 |
3.Typical Applications of Incoloy 840 Tube for Tubular Heater
Thanks to its versatile performance, Incoloy 840 tubular heater tubes are widely adopted in almost all electric heating scenarios that require medium and high temperature and frequent thermal cycles:
Air Tubular Heaters
Industrial air duct heaters, cabinet heating elements, ventilation heating systems.
Immersion Tubular Heaters
Water tank, oil tank, and chemical liquid heating elements.
4.Incoloy 840 Tube vs Stainless Steel Tube for Heater Sheath
| Comparison Dimension | Incoloy 840 tube | Standard Stainless Steel (304/316L) |
| Chemical Composition | High Nickel (~20%), High Chromium, Titanium stabilized | Medium Nickel (8–12%), High Chromium, Low Carbon |
| Max Operating Temp | Up to 800°C - 1000°C | Generally below 600°C |
| Dry-Firing Resistance | Excellent; resists deformation and scaling at high temps | Poor; prone to oxidation, blistering, and bursting |
| Corrosion Resistance | Superior against chloride stress corrosion and scaling | Moderate; prone to pitting in hard or high-chloride water |
| Thermal Stability | Stable thermal expansion; high thermal fatigue resistance | Susceptible to intergranular corrosion and thermal warping |
| Workability | Higher hardness; requires precise welding and forming | Excellent ductility; easy to form, bend, and weld |
| Material Cost | High (due to rich nickel content) | Low to Medium (highly cost-effective) |
5.Applicable Tubing Standards
5.1 ASTM (American Society for Testing and Materials)
ASTM B668
The standard specification specifically for UNS S33400 (Incoloy 840) vacuum annealed seamless and welded tubes.
ASTM B407
The general standard specification for Nickel-Iron-Chromium alloy seamless pipe and tube.
ASTM A240 / ASME SA-240
The standard for chromium and chromium-nickel stainless steel plate, sheet, and strip used to manufacture welded tubes.
DIN (European Standards)
10216-5
Seamless steel tubes for pressure purposes (Stainless steel part).
10217-7
Welded steel tubes for pressure purposes (Stainless steel part).
5.2 International Grade Cross-Reference
United States (UNS): S33400
Germany / Europe (W.-Nr. / DIN): 1.4847
Japan (JIS): NAS H840 (Proprietary grade of Nippon Yakin Kogyo)
Generic Chemical Designation: Fe-20Ni-20Cr (Iron-Nickel-Chromium base alloy)
6.Available sizes of Incoloy 840 seamless tubing for tubular heaters
We supply seamless Incoloy 840 tube. Outer diameter: 6–76mm; wall thickness 0.4–3.0mm. Length can be cut to customer's required fixed length. Tolerance & internal cleanliness strictly controlled for heater manufacturing.
7.What can we offer you about incoloy 840 tube?
Fixed-length Cutting
Tube End Machining
Heat Treatment
Surface Treatment
Forming Processing
Destructive and Non-Destructive Testing
Mechanical examining like tensile, Elongation and reduction of area.
Chemical examination
Radiographic Test
Pitting Corrosion Test
Positive material recognition
Eddy Current test
Buckling & Crushing test
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8.Packing Details of Nickel-Based Alloy Incoloy 840 Tubing
Packed in fumigation-free plywood cases. Surfaces covered with VCI anti-rust film, each piece separated by VCI anti-rust paper
Packed in fumigation-free plywood cases. Workpieces are covered with anti-rust film, separated by anti-rust paper for each piece and fastened by binding inside
FAQ
What is the maximum temperature of Incoloy 840 tubular heater tube?
It can work continuously at up to 1038°C, suitable for most medium and high-temperature industrial heating scenarios.
Is Incoloy 840 better than 304 stainless steel for heater?
Yes. Incoloy 840 has far better high-temperature resistance and thermal cycle performance than 304 stainless steel, with longer service life and more stable heating performance.
Can you provide custom size Incoloy 840 heater tubes?
Absolutely. We support customized outer diameter, wall thickness, length, and cutting processing to match various tubular heater designs.
Can you issue MTC material certificate for Incoloy 840 tube?
Full MTC test report conforming to ASTM B407 can be offered.
