Alumina Ceramic Tube
Alumina ceramic tubes are manufactured through high-temperature sintering of alumina powder, mainly divided into three grades: 92 alumina, 95 alumina and 99 high-purity alumina. Grade 92 features cost-effectiveness and suits conventional medium and high-temperature working conditions; Grade 95 has the widest application range; Grade 99 high-purity alumina boasts optimal performance in heat resistance, electrical insulation and corrosion resistance. The products are commonly milky white or light pink with dense and rigid texture. They are applied for high-temperature industrial insulation and high-temperature temperature measurement matching, compatible with thermocouples, heating wires and electrode cables to reduce losses caused by high temperature, corrosion and dust.
Common Structural Types:
1. Straight Single-hole Tube
The most common general type with one through hole. It fits threading of a single thermocouple or heating wire, and is most widely applied in kilns and resistance furnaces.
2. Multi-hole Alumina Ceramic Tube (2-hole / 3-hole / 4-hole / micro multi-hole)
Integrally formed with multiple channels. It allows routing of multiple wires at the same time to save installation space, ideal for multi-channel temperature measurement and centralized insulated wiring.
3. Sealed Round-end Tube
The end is sealed into an arc shape to block furnace dust and molten metal from entering the tube, specially matched for thermocouple probes.
4. Side-hole Special-shaped Ceramic Tube
Pre-drilled side holes on tube walls support split wiring, air ventilation and pressure relief, mostly customized for tube furnaces.
5. Solid Alumina Ceramic Rod
Solid structure without inner holes, applied as insulation supports, wear-resistant guide pillars and positioning shafts for equipment.
1. Temperature resistance: Continuous service temperature reaches 1300℃ for Grade 92, 1450℃ for Grade 95, and 1600~1700℃ for Grade 99. All grades endure higher temperatures in short-term use without softening or oxidation under high heat.
2. Insulation: Stable insulating performance under high temperature avoids electric leakage and short circuits of electric furnaces and temperature measuring circuits.
3. Corrosion resistance: Resists erosion from acids, alkalis, high-temperature flue gas, as well as scouring of molten non-ferrous metals including aluminum, zinc and copper.
4. Wear resistance & air tightness: High hardness brings compact, airtight tube walls, strong wear resistance and extended service life.
5. Thermal stability: The low thermal expansion coefficient prevents cracking under regular hot and cold alternation. The downsides are high brittleness, vulnerability to heavy impact and incapability of bending.
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Index
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Unit
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85% Al2O3
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95% Al2O3
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99% Al2O3
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99.5% Al2O3
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|
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Density
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g/cm3
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3.3
|
3.65
|
3.8
|
3.9
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|
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Water Absorption
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%
|
<0.1
|
<0.1
|
0
|
0
|
|
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Sintered Temperature
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℃
|
1620
|
1650
|
1800
|
1800
|
|
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Hardness
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Mohs
|
7
|
9
|
9
|
9
|
|
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Bending Strength(20℃))
|
Mpa
|
200
|
300
|
340
|
360
|
|
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Compressive Strength
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Kgf/cm2
|
10000
|
25000
|
30000
|
30000
|
|
|
Long Time Working Temperature
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℃
|
1350
|
1400
|
1600
|
1650
|
|
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Max. Working Temperature
|
℃
|
1450
|
1600
|
1800
|
1800
|
|
|
Volume Resistivity
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20℃
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Ω. cm3
|
>1013
|
>1013
|
>1013
|
>1013
|
|
100℃
|
1012-1013
|
1012-1013
|
1012-1013
|
1012-1013
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||
|
300℃
|
>109
|
>1010
|
>1012
|
>1012
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||
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Alumina Ceramic Through Tubes
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|||||||||
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Length(mm)
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≤2500
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||||||||
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OD*ID(mm)
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4*3
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5*3.5
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6*4
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7*4.5
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8*4
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9*6.3
|
10*3.5
|
10*7
|
12*8
|
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OD*ID(mm)
|
14*4.5
|
15*11
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18*14
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25*19
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30*24
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60*50
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72*62
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90*80
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100*90
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Alumina Content (%)
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85/95/99/99.5/99.7
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||||||||
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Alumina Ceramic Protection Tubes
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|||||||||
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Length(mm)
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≤2500
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||||||||
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OD*ID(mm)
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5*3
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6*3.5
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6.4*3.96
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6.6*4.6
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7.9*4.8
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8*5.5
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9.6*6.5
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10*3.5
|
10*7.5
|
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OD*ID(mm)
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14*10
|
15*11
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16*12
|
17.5*13
|
18*14
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19*14
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20*10
|
22*15.5
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25*19
|
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Alumina Content(%)
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95/99/99.5/99.7
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||||||||
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Alumina Ceramic Insulating Tubes
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|||
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Name
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OD(mm)
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ID(mm)
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Length(mm)
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One Pore
|
2-120
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1-110
|
10-2000
|
|
Two Pores
|
1-10
|
0.4-2
|
10-2000
|
|
Four Pores
|
2-10
|
0.5-2
|
10-2000
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1. Heat treatment furnaces, muffle furnaces, tunnel kilns: Matching sleeves for thermocouple temperature measurement
2. Industrial resistance furnaces, tube furnaces: Insulated threading tubes for heating wires and live electrodes
3. Non-ferrous metal smelting such as aluminum and zinc melting: Adapted to high-temperature molten metal environments with anti-corrosion and anti-scouring performance
4. High-temperature chemical reaction equipment, laboratory high-temperature instruments: Anti-corrosion insulated pipelines
5. High-temperature wiring for lithium battery sintering kilns, powder metallurgy sintering kilns and electronic sintering equipment
6. Wear-resistant guiding components and wire threading tubes for textile machinery
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