Alumina Protection Tubes for High-Temp Corrosion Resistance in Molten Steel

Alumina Protection Tubes for High-Temp Corrosion Resistance in Molten Steel

Core Material:
High-purity sintered alumina (Al₂O₃) ceramic. Manufactured via high-temperature sintering technology, the material possesses stable chemical inertness and strong corrosion resistance, resisting acid, alkali and oxidation in complex workshop environments.
Bulk Density:
3.4~3.89 g/cm³. Dense sintered structure with uniform internal texture, enhancing structural rigidity to withstand long-term yarn friction and mechanical load.
Maximum Use Temperature:
1400–1600°C. Excellent high-temperature stability, free from deformation and softness under continuous heat generated during high-speed wire processing.
Water Absorption:
0~＜0.2%. Near-zero water absorption avoids moisture penetration, maintaining consistent surface friction performance in humid production environments.
Flexural Strength:
300–550 MPa (20°C). Superior mechanical strength, effectively preventing cracking and chipping caused by continuous yarn tension and impact.
Processing Precision:
Custom dimensional tolerance up to ±0.01mm. Precision polished surface reaches Ra≤0.4μm, minimizing yarn abrasion and reducing filament breakage.
Service Life:
Significantly longer than conventional metal guides. Hard ceramic surface cuts replacement frequency and reduces equipment downtime.
Application:
Widely applied in textile machinery and wire processing fields. It stabilizes wire transmission, protects yarn quality and extends the service life of production equipment.

Introduction

Product Details

1. Overview of Alumina Ceramic Protection Tube
1.1 Product Brief Introduction
The alumina ceramic protection tube is a high-temperature resistant protective component made of sintered alumina ceramic. We supply 95%, 99% and 99.5% alumina grades. Compared with ordinary metal sleeves, it combines excellent high-temperature resistance, reliable insulation performance and strong corrosion resistance. It is widely used for thermocouple protection and high-temperature furnace isolation. Adopting integral sintering and precision finishing, the tube features dense structure and smooth surface, effectively shielding temperature measuring elements from high-temperature gas and molten medium erosion in industrial furnaces.
1.2 Production Technology
The alumina ceramic protection tube is manufactured by dry pressing / isostatic pressing and high-temperature sintering technology. High-purity alumina powder is formed and sintered at ultra-high temperature to gain dense bulk density. After sintering, blanks go through precision grinding and inner hole polishing. All dimensions, lengths and end shapes can be customized according to customer drawings to fit various furnace equipment.
2. Core Characteristics
2.1 Outstanding High Temperature Resistance
99% alumina grade supports continuous working temperature up to 1600°C. It maintains stable physical properties under long-term high-temperature environment and avoids softening or deformation inside heating furnaces.
2.2 High Mechanical Strength
The flexural strength reaches up to 550 MPa for 99% alumina material. It owns strong structural rigidity and can resist external impact and thermal stress cracking during furnace temperature rise and cooling cycles.
2.3 Low Water Absorption & Dense Structure
95% and 99% alumina tubes achieve zero water absorption. The compact sintered body prevents penetration of corrosive gas, greatly improving service life in harsh high-temperature atmosphere.
2.4 Controllable Thermal Expansion Performance
The thermal expansion coefficient ranges from 7.0~7.9 ×10⁻⁶/°C (25-1000°C). Stable expansion performance reduces thermal shock damage during frequent heating and cooling.
2.5 Good Thermal Conductivity & Electrical Insulation
Thermal conductivity reaches 16 W/m·K (95% alumina). Alumina material features excellent insulation, suitable for occasions requiring electrical isolation at high temperature.
3. Core Advantages
3.1 Extended Service Life
High density, zero water absorption and high temperature resistance significantly prolong service cycle compared with stainless steel protection tubes. Less frequent replacement reduces equipment downtime.
3.2 Stable Measurement Accuracy
Dense ceramic barrier protects thermocouples from oxidation and medium corrosion, guaranteeing long-term stable temperature measurement precision.
3.3 Superior Corrosion Resistance
Resistant to most high-temperature oxidizing atmospheres, acid and alkali vapor. It avoids rust and chemical erosion issues existing on metal protection sleeves.
3.4 Customized Dimensional Flexibility
We provide full customization based on customer drawings, including inner/outer diameter, tube length, thread ends and sealing structure. Suitable for experimental furnaces and all types of industrial heating equipment.
3.5 Safe & Reliable Operation
Good thermal shock resistance lowers cracking risk during temperature fluctuation. Excellent insulation prevents short-circuit risk of temperature measuring components inside furnaces.

4. Main Application Fields
4.1 Thermocouple Temperature Measurement
Serves as protection sleeves for K/S/B/R type thermocouples in industrial furnaces, kilns and laboratory heating equipment to isolate probes from harsh atmosphere.
4.2 Laboratory High-Temperature Furnace
Used as furnace liners, reaction protection tubes for box furnaces, tube furnaces and sintering furnaces in material testing and laboratory research.
4.3 Industrial Heat Treatment Furnace
Applied in quenching furnaces, annealing furnaces and ceramic sintering kilns for temperature monitoring and component isolation.
4.4 Molten Medium Isolation
Suitable for low-melting molten metal isolation and protection under non-reducing atmosphere.
4.5 Electronic & Thermal Testing Equipment
Used for high-temperature insulation protection in electronic component sintering and thermal testing fixtures.

5. Technical Data

Item	Test Condition	Unit Symbol	95%	99%	99.5%
The main chemical ingredient			Al₂O₃	Al₂O₃	Al₂O₃
Bulk Density		g/cm³	3.6	3.89	3.4
Maximum Use Temperature		°C	1450	1600	1400
Water Absorption		%	0	0	< 0.2
Flexural Strength	20°C	MPa (psi x 10³)	358 (52)	550	300
Coefficient of Thermal Expansion	25-1000°C	1 x 10⁻⁶/°C	7.6	7.9	7
Coefficient of Thermal Conductivity	20°C	W/m·K	16

Development History

Patents and certification

We’ve obtained various global certifications including CE, EMC, LVD, RoHS, FDA, MSDS, ISO 9001, SGS and TUV. We also own eight registered trademarks and forty technical patents to support independent R&D.

Our proprietary core technologies run through all product lines: porous ceramics, industrial ceramic components, special glass, metallized ceramics, liquid absorption cotton, ozone generators and silicone goods. All products are manufactured in strict accordance with international quality standards, delivering reliable and high-performance solutions that have gained wide recognition and market trust worldwide.

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Package

We adopt scientific and standardized packaging solutions tailored to product characteristics to effectively prevent collision, extrusion, dust and moisture damage. With mature global transportation system and strict shipment inspection procedures, we ensure all products remain intact and stable during long-distance delivery, providing customers with safe, efficient and reliable one-stop logistics service.

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Services

Inquiry & Customization

We provide fast and accurate quotation response for all your inquiries. Flexible OEM & ODM customization solutions are available to meet your unique product design, packaging and branding requirements.

Order Quality Control

We keep clients updated with full production progress throughout the whole order cycle. Our QC team carries out strict comprehensive pre-shipment inspection to guarantee all goods comply with your quality standards before delivery.

Customs Document Support

We prepare a full set of standard export documents including commercial invoice, packing list, certificate of origin and other certification papers, to ensure smooth global customs clearance for shipments to all destinations worldwide.

One-Stop Logistics

Multiple shipping methods including sea freight, air freight and express delivery are offered to match your schedule and budget. We supply real-time cargo tracking service so you can monitor shipment status anytime.

Flexible Payment

We support a wide range of secure international payment terms such as T/T, L/C, Western Union and other mainstream cross-border settlement methods to reduce your cross-border transaction risks.

After-Sales Support

Our professional after-sales team offers timely technical and business support all year round. We maintain steady long-term stable supply capacity to fully back up your continuous market sales and project demands.

FAQ

01 Question: Can you produce based on customers’ drawings or physical samples?

Answer: Absolutely yes. We accept technical drawings in all mainstream file formats as well as actual physical samples. Before formal production, our engineering team will provide a full professional DFM feasibility evaluation for your reference.

02 Question: How long is the production lead time for custom orders?

Answer: Sample lead time: 3–7 working days. Custom mold lead time: 5–10 working days (we will confirm the cycle separately with you for complex molds). Mass production lead time: 7–20 working days, depending on product structure complexity and order quantity.

03 Question: What’s your minimum order quantity for custom products?

Answer: We provide flexible MOQ solutions for all customized items. We will try our best to set a low minimum order volume to support your small-batch trial orders, meanwhile we can handle stable mass production to satisfy your long-term bulk demands.

04 Question: What customization services can you provide?

Answer: We support comprehensive one-stop customization, including product size, shape, appearance, precision tolerance, surface treatment, hole grooving, bending, cutting and adjustable high-temperature resistant parameters. Custom engraved LOGO and exclusive customized packaging are also available as extra personalized options upon request.

05 Question: Do you accept third-party inspection of finished products?

Answer: Yes, we fully cooperate with all mainstream authorized third-party testing institutions. Well-known organizations such as SGS, BV and other internationally recognized inspection bodies are all acceptable. We can supply complete official inspection reports and material certification documents as you require.

06 Question: Can you customize raw material options for products?

Answer: Sure. We can select and match appropriate raw materials according to your application scenarios, working conditions and performance requirements, including alumina, zirconia, quartz, silicone and other special engineering materials, and adjust related performance parameters to meet your usage standards.

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