High Temperature Resistant Silicon Nitride Riser Tube for Low Pressure Casting

                                                                                            Product Details                                                                                            

1.Overview of Silicon Nitride Ceramic Tube
1.1 Product Brief Introduction
The silicon nitride ceramic tube is a high-performance structural component manufactured with gas pressure sintered silicon nitride ceramic. Different from ordinary alumina ceramic and metal tubes, it combines high fracture toughness, excellent wear resistance, high-temperature dimensional stability and low thermal expansion coefficient. It is customized for high-temperature furnaces, fluid delivery, wire processing and corrosion-resistant equipment. Produced by integral sintering and precision machining, the tube features smooth, burr-free inner and outer surfaces. It can steadily operate under high heat, friction and corrosive environments, solving problems such as high-temperature deformation, abrasion damage and chemical corrosion of conventional metal and ceramic tubes.
1.2 Production Technology
The silicon nitride ceramic tube adopts gas pressure sintering (GPS) technology. High-purity silicon nitride powder is formed by isostatic pressing, then sintered under high-pressure nitrogen atmosphere to achieve a dense bulk density of 3.25 g/cm³. After sintering, blanks go through precision grinding and mirror polishing to guarantee smooth surfaces. All inner diameter, outer diameter and length specifications can be customized per customer drawings for diverse industrial equipment.
2. Core Characteristics
2.1 High Hardness & Wear Resistance
With Rockwell hardness ≥75 HRA, the silicon nitride ceramic tube maintains stable performance under long-term friction. Its dense sintered structure effectively resists surface abrasion from flowing media, wires and raw materials, greatly lowering surface scratching and wear compared with metal pipes.
2.2 Excellent Fracture Toughness
The material achieves fracture toughness of 6–9 MPa·m¹ᐟ², effectively preventing crack expansion under instantaneous impact and thermal shock. This characteristic sharply reduces chipping and breakage risks compared with ordinary brittle oxide ceramics.
2.3 High Structural Rigidity
With elastic modulus of 300–320 GPa, the ceramic tube maintains high dimensional stability under continuous mechanical load. It resists deformation under long-term pressure, keeping consistent dimensional accuracy during continuous operation.
2.4 Stable Thermal Performance
Thermal expansion coefficient stands at 3.1–3.3 ×10⁻⁶/℃. It maintains precise dimensions amid frequent temperature changes. Thermal conductivity of 15–20 W/(m·K) helps uniform heat transfer and avoids local overheating during continuous high-temperature service.
2.5 Superior Electrical Insulation
Volume resistivity reaches 10¹⁴ Ω·cm, delivering outstanding insulation performance. It prevents static accumulation during high-speed wire passage or medium flow, avoiding electrostatic hazards in precision and electronic production lines.
2.6 Reliable Batch Consistency
With Weibull modulus of 12–15 m, gas pressure sintered silicon nitride provides stable mechanical performance between batches. Every batch of silicon nitride tubes maintains uniform quality, supporting stable equipment operation and standardized spare part management.
3. Core Advantages
3.1 Extended Service Life
High hardness, reliable fracture toughness and dense microstructure deliver outstanding durability. Under equal working conditions, it serves far longer than ordinary metal and alumina ceramic tubes, cutting equipment downtime and replacement frequency.
3.2 Stable Transmission & Protection
Precision machined smooth inner surface minimizes abrasion to passing wires, fibers or flowing materials. It reduces filament breakage, particle contamination and medium turbulence, improving finished product yield.
3.3 Low Maintenance Cost
Silicon nitride ceramic will not rust and withstands most acid, alkali and organic corrosive media. No frequent surface anti-corrosion treatment or lubrication required, reducing long-term factory operating expenses.
3.4 Customized Dimensional Flexibility
We provide full customization according to customer drawings, including inner diameter, outer diameter, length, flanges and special end structures. We can produce matching tubes for furnace equipment, wire machinery and chemical processing devices.
3.5 Safe and Stable Operation
Excellent insulation avoids static discharge risks in continuous production. Stable thermal properties prevent thermal deformation and cracking caused by long-term heating, supporting safer continuous industrial production.

4. Main Application Fields
4.1 High-Temperature Industrial Furnace Equipment
Used as protective tubes, heating element sleeves and atmosphere delivery tubes in sintering furnaces, annealing furnaces and laboratory furnaces. It keeps stable shape under continuous high temperature and isolated corrosive furnace atmosphere.
4.2 Wire & Fiber Processing Machinery
Serves as threading tubes and protective sleeves for textile fiber, carbon fiber and glass fiber production. The smooth inner wall protects filaments from scratching during high-speed transportation.
4.3 Corrosion-Resistant Fluid Pipeline
Applied for conveying weakly acidic, alkaline and organic media in chemical, new energy and laboratory facilities. Resists chemical erosion better than ordinary metal pipelines.
4.4 Precision Electronic Equipment
Used as insulating protective sleeves for high-temperature electronic assemblies. High volume resistivity prevents short circuit and static interference.
4.5 Powder & Granule Conveying
Ideal for abrasive raw material transportation. Strong wear resistance reduces pipeline abrasion and avoids metal impurity contamination of raw materials.
4.6 Equipment Spare Part Upgrade
Supplied as wear-resistant replacement parts for industrial equipment renovation. Factories can replace traditional metal or alumina tubes with silicon nitride versions to lower overall operation costs.

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