Silicon Nitride Thermocouple Protection Tube | Si3N4 Sheath for Molten Aluminum
Custom & standard Si₃N₄ ceramic thermowells specially optimized for aluminum melting, holding, die casting and aluminum alloy processing. Solve core pain points of ordinary ceramic tubes cracking, corrosion and short service life in aluminum liquid environment.
Product Overview (Aluminum Processing Focused)：
Most ordinary alumina and silicon carbide thermocouple tubes are easily eroded, infiltrated and cracked by high-temperature molten aluminum, resulting in frequent thermocouple failure, unstable temperature monitoring and increased production downtime costs.
Our reaction-bonded silicon nitride (Si₃N₄) thermocouple protection tubes are professionally customized for the high-corrosion and rapid temperature change working conditions of aluminum processing. The unique ceramic molecular structure realizes complete non-wetting with molten aluminum, which fundamentally avoids aluminum liquid penetration and tube body corrosion.
Stable and durable in long-term aluminum melting and die casting production, it effectively protects K, N, S-type thermocouple sensors, greatly reduces replacement frequency, and ensures real-time and accurate temperature control of aluminum liquid, which is the core consumable for high-efficiency production of aluminum processing enterprises.
Technical Parameters (Aluminum Processing Standard)：
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Item
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Professional Parameters for Aluminum Industry
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Material
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Reaction-bonded Silicon Nitride (Si₃N₄)
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Long-term Working Temperature
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≤1250℃ (Perfect for aluminum liquid working conditions)
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Short-term Peak Temperature
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1400℃
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Anti-molten Aluminum Performance
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Excellent (Zero wetting, no corrosion)
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Thermal Shock Resistance
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Grade Super (Suitable for frequent temperature cycles of aluminum furnace)
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Applicable Thermocouple
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K / N / S Type (Common models for aluminum processing)
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Optional Structure
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Closed-end / Straight tube / Step tube / Flange type (Custom for aluminum furnace installation)
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Custom Service
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Support OD, ID, length, structure customized according to aluminum processing equipment
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Standard Sizes for Aluminum Processing Equipment：
Conventional stock sizes for mainstream aluminum melting furnaces, holding furnaces and die casting machines (OD×ID×L):
- Φ20×14×300mm / Φ22×16×400mm (Small aluminum die casting machine)
- Φ25×18×500mm / Φ28×20×600mm (Conventional aluminum holding furnace)
- Φ30×22×700mm / Φ32×24×800mm (Large aluminum melting furnace)
Full Customization Available: We can produce non-standard sizes and special structures according to your aluminum equipment drawings and on-site working conditions.
Material Comparison | Why Choose Si3N4 for Aluminum Processing?
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Protection Tube Material
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Molten Aluminum Corrosion Resistance
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Thermal Shock Resistance
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Service Life in Aluminum Furnace
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Cost Performance
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Silicon Nitride (Si₃N₄)
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★★★★★ No infiltration, no adhesion
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★★★★★ No cracking in frequent cooling & heating
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6-12 months (Long-term stable use)
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Highest (First choice for aluminum industry)
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Silicon Carbide (SiC)
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★★★☆☆ Easy to be infiltrated by aluminum liquid
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★★★☆☆ Easy to crack under rapid temperature change
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2-3 months
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Low
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High-purity Alumina
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★☆☆☆☆ Severe aluminum liquid corrosion
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★★☆☆☆ Easy brittle cracking
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1 month or less
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Very low
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Application Scenarios in Aluminum Industry：
- Aluminum Melting Furnace: Real-time temperature monitoring of high-temperature molten aluminum in industrial aluminum melting furnaces.
- Aluminum Holding Furnace: Long-term constant temperature detection of aluminum liquid in heat preservation furnaces.
- Aluminum Die Casting Machine: On-line temperature measurement of aluminum liquid in die casting production system.
- Aluminum Alloy Smelting: Temperature control for production of aluminum-magnesium, aluminum-zinc and other alloy materials.
- Aluminum Liquid Transfer Ladle: Mobile temperature detection in the process of aluminum liquid pouring and transfer.
- Aluminum Profile Processing Furnace: High-temperature temperature monitoring for aluminum profile heat treatment and smelting.
Aluminum Industry Exclusive FAQ：
Q1: Is this tube specially used for molten aluminum? Can it avoid aluminum liquid adhesion?
A: Yes. This Si3N4 protection tube is optimized for aluminum processing scenarios. It has physical non-wetting property with molten aluminum, which can completely avoid aluminum liquid adhesion and penetration, and will not cause tube body blockage and corrosion failure.
Q2: What is the service life in aluminum melting furnace?
A: Under normal aluminum melting and heat preservation working conditions, the continuous service life can reach 6-12 months, which is 3-5 times longer than ordinary alumina tubes, greatly reducing equipment shutdown and replacement costs.
Q3: Can it withstand frequent furnace opening and cooling in aluminum production?
A: Absolutely yes. The product has excellent thermal shock resistance, which can adapt to the frequent temperature rise and fall of aluminum furnaces in daily production, and will not crack or damage due to sudden cooling and heating.
Q4: What thermocouples are suitable for aluminum liquid temperature measurement?
A: It is perfectly compatible with K-type and N-type thermocouples most commonly used in aluminum processing, and also supports S-type high-precision temperature measurement sensors.
Q5: Are there any usage precautions in aluminum working conditions?
A: This product is exclusive for molten aluminum, aluminum alloy and zinc alloy. It is not suitable for molten iron, molten steel and strong alkaline slag environment; avoid violent impact during installation.
