High-temperature alumina and corundum furnace tubes
Alumina furnace tubes (work tubes) in C799 alumina, open at both ends and cut to length. 12 sizes from 30×20 to 80×70 mm (OD × ID) are usually in stock, including 2 m lengths at OD 30 and 40 mm. In air they are used up to 1,750 °C hanging vertically and 1,650 °C lying horizontally.
- outer diameter
- 30–100 mm
- outer diameter
- maximum length
- 2000 mm
- maximum length
- usually in stock
- 12 sizes
- usually in stock
- to ship
- ~3 days
- to ship
Furnace tubes from our factory
See all 9 photos
Configurations
- Open-ended process tube
- Large-diameter tube
- Custom tube
Applications
- Laboratory furnaces
- Industrial resistance furnaces
- Electric furnaces
- Heat-treatment furnaces
- Controlled-atmosphere processing
Ordering
- Minimum order, non-standard parts
- 100 pcs
- Usually, per item made to your drawing or sample.
- Samples for approval
- 5–10 pcs
- Usually sent for you to approve before the order runs.
- Production lead time
- 25–30 days
- Usual production cycle for non-standard parts.
- Standard sizes from stock
- ~3–7 days
- Stock covers most standard sizes. Small orders ship in about 3 days, bulk orders in about 7 days.
Typical terms. Quantities and dates for your order are confirmed in its quotation.
Standard sizes
Size range
- OD
- 30–100 mm
- Length
- 1000–2000 mm
Other sizes made to drawing; tolerances confirmed per quotation.
Dimensions in mm
| OD | ID |
|---|---|
| 30 × 20 mm | 20 |
| 30 × 23 mm | 23 |
| 32 × 25 mm | 25 |
| 35 × 25 mm | 25 |
| 40 × 30 mm | 30 |
| 45 × 35 mm | 35 |
| 50 × 40 mm | 40 |
| 55 × 45 mm | 45 |
| 60 × 50 mm | 50 |
| 65 × 55 mm | 55 |
| 70 × 60 mm | 60 |
| 80 × 70 mm | 70 |
Standard sizes usually ship from stock in 3–7 days. Lengths are cut to order.
From our factory's standard-size list, September 2026.
Secondary operations
Done in the factory after forming. Hole sizes and positions are confirmed from your drawing.
- Cut to lengthTubes cut to the ordered length.
- End slotsA slot across a closed tip, or slots cut into open tube and insulator ends.
- Side holes and perforated tubesOne or two side holes, or a line of holes along the tube.
Grade and material data
Alumina and corundum. Our standard grade is C799 alumina, 99.5% Al₂O₃, and we supply 95% white alumina where a drawing names C 610. Purity and maximum temperature are confirmed per SKU at quotation.
Full material data| Material class | Al₂O₃ % | Working temperature °C | Hardness, Mohs |
|---|---|---|---|
| High-alumina | >85 | 1300–1450 | 8 |
| Corundum | 99–99.5* | 1600–1800* | 8-9 |
* Stated per SKU: the grade and maximum temperature of each part are confirmed in its quotation.
Guides
Sizes, grades and tolerances in more detail.
- Buyer FAQ: minimum order, lead time, stock, samples, ISO 9001 and test reports What buyers ask before ordering: minimum order, lead time, which sizes are in stock, samples, the ISO 9001 certificate, lab reports and packing.
- How to choose an alumina crucible, lid or boat: shape, capacity and fit Size a crucible from the charge, compare shapes of the same capacity, pick the lid, and decide between a boat and a crucible.
- Alumina furnace tube sizes: our stock tubes next to the work tubes furnace makers list Our stock alumina work tube sizes beside the tubes Nabertherm, MTI and Carbolite Gero list, with what to measure on the tube you replace.
- Alumina density, melting point and thermal properties by purity Density in g/cm³ and kg/m³, melting point, thermal conductivity and expansion for 96% and C799 alumina, with our forming-method data and a weight calculator.
- Low-sodium alumina: Na₂O content, why it matters and how to specify it What low-sodium alumina means, the Na₂O, SiO₂, Fe₂O₃ and CaO in three years of lab analyses of our 99.5% alumina, why sodium matters for semiconductors and hot insulation, and what to put on the request.
- DIN 40680 tolerances for alumina tubes, and what buyers write on orders The OD, ID and length tolerances on this year's orders for protection tubes and insulators, set against the DIN 40680 general tolerances.
- Alumina or quartz tube for a tube furnace: temperature limits, vacuum and heating rates When a quartz work tube is enough, when you need alumina, and what furnace makers say about vacuum, heating rates and sag. With our alumina tube sizes and the boats that fit inside.
- Alumina maximum temperature: why tubes are rated 1,600 °C or 1,800 °C, and what lowers it Why the same alumina is quoted at 1,400, 1,600 and 1,800 °C, the limits by grade and by use, and what brings them down: vacuum, load, fast heating, alkali and glass.
- Alumina thermal shock: why ceramic tubes crack, and how to stop it Why high-purity alumina cracks on fast heating or cooling, the published ramp rates and insertion speeds, and what to change for protection tubes, work tubes and crucibles.
- How to cut an alumina tube, and when to order it cut The diamond blade, speed, coolant and support that tool makers give for cutting fired alumina tube, and what a cut-to-length order from us looks like.
- Alumina vs aluminum (aluminium): the ceramic and the metal compared Alumina is aluminium oxide, a white ceramic; aluminium is the metal. Melting point, density and conductivity side by side, the names suppliers use, and how to order the right one.
- How alumina tubes are made: forming, sintering at 1,760 °C, and size limits Our process step by step: extrusion and slip casting with their largest sizes, the kiln temperatures for alumina and porcelain tubes, straightness, and what each step means for a drawing or order.
- Alumina boat crucibles: sizes, shapes and which boat fits your tube furnace How to check that a boat passes your work tube, a finder for any tube ID, our boats by shape and by furnace tube, lids, heating rates, and what to send.
Questions buyers ask
- Which furnace tube sizes are in stock?
- 12 open-ended sizes from 30×20 to 80×70 mm (OD × ID) are usually in stock, and we cut them to the length you order.
- Do you have long alumina furnace tubes in stock?
- Yes: Ø80, 75, 70, 65 and 60 mm at 1–1.2 m; Ø50, 45 and 35 mm at 1.5 m; Ø40 and 30 mm at 2 m.
- What temperature can an alumina furnace tube take?
- In air, our corundum tubes are used up to 1,750 °C hanging vertically and 1,650 °C lying horizontally. A horizontal tube carries its own weight across the span, which is why it is rated lower. Vacuum, load, fast heating and alkali vapour bring the limit down.
- What is the largest tube you can make?
- Extruded tubes up to 17×10 mm (OD × ID) and slip-cast tubes up to 100×90×1000 mm (OD × ID × length).
- What alumina grade are the furnace tubes?
- Our standard grade is C799 alumina, 99.5% Al₂O₃. Where a drawing names C 610, we supply 95% white alumina instead.
- Can you cut slots or holes in a furnace tube?
- Yes. Besides cutting to length, we cut end slots and side holes. Mark their position and size on the drawing.
- How fast do stock furnace tubes ship?
- Stock sizes usually ship in about 3 days for a small order and about 7 days for a bulk order. Tubes made to your drawing usually take 25–30 days, from 100 pieces.
What to send for a quote
- 01OD, ID and length
- 02End finish, flanges or other features, with a drawing if you have one
- 03Maximum operating temperature and atmosphere
- 04Heating and cooling rates, if known
- 05Al₂O₃ grade
- 06Quantity
Next family:Alumina and corundum crucibles and boats
Request a quote
Get a quotation for furnace tubes.
Tell us the dimensions, grade and quantity. We confirm the grade, dimensions and tolerances in each quotation. Our yearly lab reports are available on request.