Silicon Nitride (Si3N4) Ceramic Heater Protection Tubes
Manufactured with China’s most advanced cold isostatic pressing and gas pressure sintering technology, our Si3N4 heater protection tubes are engineered for extreme high-temperature environments like aluminum melting furnaces. Ultra-smooth surface prevents molten metal adhesion. ISO9001 certified factory with 5,000+ annual capacity, common sizes in stock for fast delivery.
- Technical Performance
| Material Composition | Si3N4 (Silicon Nitride) |
| Density | 3.20±0.4 g/cm³ |
| Bending Strength | ≥800-1000 MPa (at room temperature) |
| Fracture Toughness | ≥7.0-9.0 MPa·m^1/2 |
| Thermal Conductivity | 22-24 W/(m·K)-1 |
| Hardness | 92-94 Gpa |
In the aluminum smelting and metal processing industry, frequent heater damage and replacement has long plagued production facilities, increasing maintenance costs while causing production interruptions and efficiency losses. Traditional protection tube materials are susceptible to corrosion, molten metal adhesion, or mechanical damage in high-temperature molten metal environments, with average service life of only 3-6 months.
Our Si3N4 silicon nitride heater protection tubes, manufactured using China’s most advanced cold isostatic pressing and gas pressure sintering technology, completely solve these problems. Ultra-smooth surface treatment ensures molten metal won’t adhere, excellent thermal conductivity guarantees heating efficiency, silicon nitride’s inherent high strength and corrosion resistance enable long-term stable operation in extreme environment, while offering more competitive pricing and faster local supply services.
Product Applications
Heater protection applications for high-performance aluminum alloy melting in casting furnaces.
- Aluminum Processing Industry: Aluminum profile extrusion, Aluminum sheet/strip production, Aluminum foil manufacturing, Recycled aluminum recovery
- Automotive Manufacturing Industry: Engine block die-casting, Transmission housing production, Aluminum alloy wheel hub manufacturing, Body structural component die-casting, New energy vehicle battery tray
- Die-Casting Industry: Cold chamber die-casting, Hot chamber die-casting, Semi-solid die-casting, Vacuum die-casting, Die-casting mold temperature control
- Aerospace Industry: High-purity, high-performance alloy preparation, Investment casting for aircraft engine components, High-reliability scenarios with special requirements
The Si3N4 powder we use comes from certified high-quality domestic and international suppliers. Each batch of raw materials must undergo rigorous inspection upon arrival: chemical composition analysis (ICP-MS), particle size distribution testing (laser particle size analyzer), purity detection, impurity content analysis, etc.
Cold isostatic pressing is a critical process ensuring product density and uniformity. We are equipped with advanced automatic pressure control systems capable of precisely controlling pressure and dwell time. After each batch forming, density detection and dimensional measurement are performed to ensure green body quality stability.
Ceramic protective tube products require precision machining to achieve final dimensional and surface quality requirements. We use dedicated ceramic processing equipment (diamond grinding wheels, ultrasonic processing, etc.), avoiding microcracks during processing.
Why choose SF-Foundry Ceramic Protection Tubes?
Choosing our Si3N4 silicon nitride heater protection tubes, you get not just a product but a complete value system: Globle quality + China pricing + fast delivery + professional custom service. Using China’s most advanced manufacturing technology, we provide aluminum processing and die-casting companies with high-performance, cost-effective solutions, helping you reduce total cost, improve production stability and product quality, and enhance market competitiveness. This is our promised value—making high quality affordable and reliable supply readily accessible.
SF-Foundry Related Products
Need Custom Riser Tubes for Your Casting Process?
Contact SF-Foundry’s technical team and provide your casting parameters: aluminum type, temperature, mold size, etc. We will recommend the best solution!
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Silicon nitride ceramics possess excellent high-temperature strength, superior thermal shock resistance, high thermal conductivity, and extremely strong resistance to corrosion and erosion by molten metals (especially aluminum, zinc, and magnesium). These characteristics allow it to operate stably for extended periods in high-temperature furnace environments, protecting the heater from damage.
Compared to alumina, silicon nitride offers:
- Higher thermal shock resistance: It can withstand more drastic temperature changes and is less prone to cracking.
- Better mechanical strength: It maintains high strength and toughness at high temperatures, providing stronger resistance to mechanical impact.
- Superior resistance to metal corrosion: It is especially suitable for highly reactive aluminum melt environments, resulting in a longer service life.
- Good surface finish: Molten metal is less likely to adhere, making cleaning and maintenance easier.
Key considerations include:
- Ensure the flange mounting surface is flat and tightened evenly to avoid cracking of the tube due to uneven stress.
- During initial heating or when the operating temperature changes drastically, it is recommended to follow an appropriate heating/cooling procedure to fully utilize the material’s excellent thermal shock resistance.
- Avoid subjecting the protection tube to strong impacts from sharp objects during installation and use.
This product is widely used in the melting, holding, and die-casting processes of aluminum, aluminum-silicon alloys, zinc, magnesium, and their alloys. Common applications include: aluminum melt holding furnaces, melting furnaces, zinc pots, die-casting machine pouring systems, etc. For other metals or salt bath environments, please consult us beforehand to confirm compatibility.
This is an advanced process combination for manufacturing high-performance engineering ceramics:
- Cold isostatic pressing: Ensures uniform density of the green body, reduces defects, and lays a good foundation for subsequent sintering.
- Pressure Sintering: This process effectively promotes material densification, resulting in high-strength, high-reliability products with near-theoretical density, uniform microstructure, and stable performance.
We achieve high surface finish through meticulous raw material processing and advanced sintering process control. The smooth surface significantly reduces the adhesion and sticking of molten metal, lowering maintenance and cleaning difficulties. It also reduces the starting points for corrosion of the pipe wall by molten metal, helping to extend service life.
Yes. We support customization of dimensions, shapes (such as special flange designs), thread specifications, etc., according to customers’ specific needs. Please provide detailed drawings or technical requirements, and our engineering team will contact you.
You are welcome to contact us by phone, email, or online inquiry. Please provide as much information as possible regarding your application environment, operating temperature, media type, required dimensions, and connection method, so that we can provide you with the most accurate product recommendations and technical support.