What are alumina single bore tubes used for?

Alumina single bore tubes are used for thermocouple protection, sensor housings, gas paths, electrical insulation and high-temperature furnace assemblies. The single central bore helps position a probe, conductor, gas line or small component inside a ceramic protective tube.

What is the difference between single bore and multi-bore alumina tubes?

A single bore tube has one central channel and is often selected for one sensor, conductor or gas path. Multi-bore tubes have two or more channels and are used when several wires or probes need separation inside the same ceramic body. Single bore tubes are usually simpler to install and easier to specify for one-path applications.

Can ADCERAX make open-end and closed-end alumina single bore tubes?

Yes. ADCERAX can review both open-end and closed-end alumina single bore tube designs according to drawings or samples. Open-end tubes are often used for gas flow, wire routing or probe insertion, while closed-end tubes are commonly used for thermocouple and sensor protection.

Which alumina purity should I choose for a custom single bore tube?

The suitable alumina grade depends on temperature, atmosphere, insulation requirement, contamination sensitivity and cost target. Common options include 96%, 99%, 99.5% and higher-purity alumina. For analytical, sensor or high-temperature applications, higher-purity alumina is often preferred after application review.

What information is needed for a quotation?

Please provide OD, ID, length, wall thickness, end design, tolerance, surface finish, alumina purity, quantity, working temperature, atmosphere and application type. A drawing or sample photo helps confirm manufacturability and quotation accuracy.

Can alumina single bore tubes be customized with threads, slots or special ends?

Yes. Depending on tube size, wall thickness and machining feasibility, ADCERAX can review chamfers, slots, stepped ends, threaded features, polished surfaces and other drawing-based structures. Complex features should be confirmed before production because ceramic machining limits depend on geometry.

Custom Alumina Single Bore Tubes for Furnaces

What Are Alumina Single Bore Tubes?

Alumina single bore tubes are ceramic tubes made from aluminum oxide with one central through-hole or closed-end bore. They are commonly used to protect thermocouples, sensors, conductors and gas paths in high-temperature furnaces, laboratory instruments, electrical insulation assemblies and corrosive process environments.

Engineering Benefits of Alumina Single Bore Tubes

High-temperature stability: Alumina tubes help protect sensors, wires and process channels in furnace and thermal processing equipment.
Electrical insulation: The ceramic body provides insulation between conductors, heating zones and metal fixtures.
Controlled single-bore geometry: A single central bore supports accurate placement of thermocouples, probes, gas lines or small components.
Chemical resistance: High-purity alumina helps reduce contamination risk in many laboratory and industrial atmospheres.
Drawing-based customization: OD, ID, length, wall thickness, end shape, slots, threads, chamfers and surface finish can be reviewed according to your design.

Typical Material Properties of Alumina Ceramic Tubes

The following values are typical reference data for alumina ceramic materials. Actual performance depends on purity grade, forming process, sintering condition, tube geometry and operating environment. Please confirm final material grade and property requirements before ordering.

Property	Unit	96% Al₂O₃	99% Al₂O₃	99.5% Al₂O₃	99.6% Al₂O₃	99.7% Al₂O₃	99.8% Al₂O₃	99.9% Al₂O₃	99.99% Al₂O₃
Alumina content	%	96	99	99.5	99.6	99.7	99.8	99.9	99.99
Density	g/cm³	3.6-3.75	3.83	3.89	3.91	3.92	3.93	3.94	3.98
Color	–	white	Ivory	Ivory	Ivory	Ivory	Ivory	Ivory	Ivory
Water absorption	%	0	0	–	0	0	0	0	0
Young’s modulus (Elastic modulus)	GPa	300	350	375	356	357	358	359	362
Shear modulus	GPa	–	–	152	–	–	–	–	–
Bulk modulus	GPa	–	–	228	–	–	–	–	–
Poisson’s ratio	–	–	–	0.22	–	–	–	–	–
Compressive strength	MPa	1910	2210	2500	2552	2554	2556	2558	2570
Flexural strength	MPa	260	300	340	345	346	347	348	365
Fracture toughness	MPa·m¹ᐟ²	–	–	4	–	–	–	–	–
Hardness	GPa	14.5	17	17	23	24	25	26	30
Thermal conductivity	W/m·K	20	31	31	31-33	31-33	31-33	31-35	31-35
Thermal shock resistance ΔT	°C	–	–	–	222	223	224	225	228
Maximum use temperature (no load)	°C	1450	1680	≤1750	1755	1760	1765	1770	1800
Coefficient of thermal expansion	10⁻⁶/°C	7.6	7.6	7.6	7.6	7.5	7.5	7.4	7.4
Volume resistivity	Ω·cm	>1×10¹⁴	>1×10¹⁴	>1×10¹⁴	>1×10¹⁴	>1×10¹⁴	>1×10¹⁴	>1×10¹⁴	>1×10¹⁴
Dielectric constant (relative permittivity)	–	9.2	9.5	9.8	9.83	9.84	9.85	9.86	9.92
Dielectric strength	kV/mm	15	19	16.9	23.2	23.4	23.6	23.8	24
Dissipation factor (loss factor @ 1 kHz)	–	–	–	0.0002	–	–	–	–	–

Specifications of Alumina Single Bore Tubes

Item No.	Diameter (mm)	Thickness (mm)	Purity
TE-AT-20001-1	Customize

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Single Bore Alumina Tubes Packaging:

Each tube is individually wrapped in foam and packed in a rigid cardboard box.
Optional ceramic end caps are available upon request.
Bulk packaging available for wholesale orders.

Applications of Custom Alumina Single Bore Tubes

Thermocouple Protection in High-Temperature Furnaces

Alumina single bore tubes are commonly used as thermocouple protection sheaths in tube furnaces, kilns, heat treatment equipment and laboratory thermal systems. The ceramic tube helps isolate the sensing element from direct flame, furnace atmosphere, particles and mechanical contact.

For this application, buyers usually need to confirm tube length, bore diameter, closed-end or open-end design, mounting clearance and thermal cycling conditions.

Electrical Insulation and Heating Assemblies

Single bore alumina tubes can be used as ceramic insulators for conductors, heating elements, lead wires and high-temperature electrical assemblies. The tube geometry helps maintain separation between conductive parts while resisting heat and many process atmospheres.

For insulation applications, the key design factors include alumina purity, wall thickness, dielectric requirement, bore fit, fixture material and installation stress.

Gas Sensor and Probe Protection

Custom alumina single bore tubes can protect gas sensors, probes and small analytical components in high-temperature or chemically demanding environments. A closed-end design may be used when the sensor needs isolation from direct gas flow, while an open-end tube may be selected for gas path or probe insertion.

For sensor applications, buyers should confirm bore tolerance, end design, surface finish, response-time requirements and atmosphere compatibility.

Laboratory and Analytical Equipment

Alumina single bore tubes are used in laboratory furnaces, thermal analysis fixtures and material testing systems where dimensional consistency, contamination control and high-temperature insulation are important.

For analytical equipment, polished bore surfaces, controlled ID tolerance and suitable cleaning procedures may help reduce particle retention and improve repeatability.

OEM Ceramic Tube Assemblies

For OEM equipment builders, alumina single bore tubes can be designed as build-to-print ceramic components. ADCERAX can review drawings for OD, ID, length, chamfers, slots, threads, end faces, surface finish and inspection requirements before production.

Handling and Usage Guidelines for Alumina Single Bore Tubes

Installation

1. Support long tubes evenly to reduce bending stress during installation.
2. Avoid forcing the tube into a metal fixture when the fit is too tight.
3. Use suitable ceramic-compatible clamps, soft pads or support sleeves when needed.
4. Confirm whether the design requires an open-end or closed-end tube before installation.
Heating and Cooling

1. Use gradual heating and cooling whenever possible to reduce thermal shock risk.
2. Avoid sudden contact with cold surfaces after high-temperature operation.
3. Do not apply mechanical load to the tube during rapid temperature change.
4. Confirm the recommended temperature range according to the selected alumina grade and tube geometry.
Cleaning and Inspection

1. Remove loose particles from the bore before reuse in analytical or sensor applications.
2. Avoid abrasive tools that may create surface scratches or microcracks.
3. Inspect the tube for cracks, edge chips, discoloration or bore blockage before installation.
4. Replace the tube if visible damage may affect sealing, insulation or sensor alignment.
Storage

1. Store tubes in a dry, clean and vibration-free area.
2. Use soft dividers or foam packaging to avoid direct tube-to-tube contact.
3. Keep long tubes horizontally supported to reduce bending stress during storage.

Custom Alumina Single Bore Tubes FAQ

What are alumina single bore tubes used for?
Alumina single bore tubes are used for thermocouple protection, sensor housings, gas paths, electrical insulation and high-temperature furnace assemblies. The single central bore helps position a probe, conductor, gas line or small component inside a ceramic protective tube.
What is the difference between single bore and multi-bore alumina tubes?
A single bore tube has one central channel and is often selected for one sensor, conductor or gas path. Multi-bore tubes have two or more channels and are used when several wires or probes need separation inside the same ceramic body. Single bore tubes are usually simpler to install and easier to specify for one-path applications.
Can ADCERAX make open-end and closed-end alumina single bore tubes?
Yes. ADCERAX can review both open-end and closed-end alumina single bore tube designs according to drawings or samples. Open-end tubes are often used for gas flow, wire routing or probe insertion, while closed-end tubes are commonly used for thermocouple and sensor protection.
Which alumina purity should I choose for a custom single bore tube?
The suitable alumina grade depends on temperature, atmosphere, insulation requirement, contamination sensitivity and cost target. Common options include 96%, 99%, 99.5% and higher-purity alumina. For analytical, sensor or high-temperature applications, higher-purity alumina is often preferred after application review.
What information is needed for a quotation?
Please provide OD, ID, length, wall thickness, end design, tolerance, surface finish, alumina purity, quantity, working temperature, atmosphere and application type. A drawing or sample photo helps confirm manufacturability and quotation accuracy.
Can alumina single bore tubes be customized with threads, slots or special ends?
Yes. Depending on tube size, wall thickness and machining feasibility, ADCERAX can review chamfers, slots, stepped ends, threaded features, polished surfaces and other drawing-based structures. Complex features should be confirmed before production because ceramic machining limits depend on geometry.

Information Needed for a Custom Alumina Single Bore Tube Quote

To prepare an accurate quotation, please send the drawing, sample photo or technical requirements. The following details help our team review manufacturability and material suitability before pricing.

Required Information	Why It Is Needed
Outer diameter, inner diameter and length	These dimensions determine forming, machining, inspection and packaging requirements.
Open-end or closed-end structure	The end design affects forming method, sensor protection, sealing and gas flow direction.
Alumina purity grade	Purity affects high-temperature use, insulation, contamination control and cost.
Required tolerance and surface finish	These details affect assembly fit, bore clearance, cleaning behavior and machining cost.
Working temperature and atmosphere	These conditions help confirm material suitability and thermal cycling risk.
Application type	Thermocouple protection, sensor housing, gas path, insulation and furnace use may require different design priorities.
Quantity and delivery requirement	Quantity affects production planning, packaging method and quotation structure.

Catalogue No.	TE-AT-20001-1
Material	Al2O3
Purity	96% 99% 99.5% 99.7%
Maximum Working Temperature	1450°C (95%) – 1730°C (99.7%)
Dimensions/Sizes	Download PDF

Parameter	Available / Review Range	Why It Matters for the Application
Alumina purity	96%, 99%, 99.5%, 99.7% or higher grades can be reviewed.	Purity affects temperature resistance, contamination control, electrical insulation and chemical compatibility.
Outer diameter and inner diameter	Custom OD and ID can be produced according to drawings or samples.	OD controls fixture fit and mechanical strength, while ID controls sensor, wire, gas flow or probe clearance.
Wall thickness	Reviewed according to tube size, length, load and installation method.	Wall thickness affects mechanical stability, thermal shock behavior and breakage risk during installation.
Length	Standard and custom lengths are available, including long furnace or sensor protection tubes.	Length must match furnace depth, heating zone position, sensor insertion depth and support spacing.
End design	Open both ends, closed one end, stepped, slotted, threaded or chamfered ends can be reviewed.	End design determines sealing, sensor protection, gas flow direction and assembly stability.
Tolerance	Controlled tolerance can be reviewed based on bore size, length and machining feasibility.	Tolerance is important for thermocouple fit, probe alignment, gas path control and OEM assembly repeatability.
Surface finish	As-fired, ground, polished or glazed surfaces can be selected according to the application.	Surface finish affects contamination control, insertion friction, sealing contact and cleaning behavior.
Working atmosphere	Air, inert gas, selected reducing gas or process gas should be confirmed before quotation.	The atmosphere affects material selection, thermal cycling risk and long-term ceramic stability.