RBSIC Tube and Pipe

Advantages

1. Excellent thermal conductivity achieves energy-saving heat transfer
The thermal conductivity of RBSIC tube and pipes is 150-180 W/m · K at room temperature and 40-50 W/m · K at 1200 ° C. The thermal conductivity efficiency at high temperatures is 5-8 times higher than that of alumina (25-30 W/m · K) and 10-12 times higher than that of stainless steel (12-15 W/m · K -). In the radiation tube, this means that the combustion heat is transferred faster and more evenly to the furnace, reducing the wall temperature gradient and accelerating the start-up speed by 15-25%. In steady-state operation, higher conductivity allows the burner to operate at lower flame temperatures to achieve the same heat output, reduce the formation of nitrogen oxides, and extend the life of the burner and pipeline. In heat exchangers, RBSIC tubes recover 30-50% more waste heat than metal or alumina tubes, directly reducing fuel consumption. For energy intensive industries, this typically takes 6-18 months to recoup pipeline investments.
2. Low thermal expansion and high thermal shock resistance during intermittent operation
RBSIC thermocouple tubes can be removed from a 1100 ° C furnace and placed on a room temperature table without breaking, while alumina is almost certain to break. For batch furnaces, batch kilns, and frequent start stop cycles, this is crucial - metal tubes will experience thermal fatigue after 50-100 cycles, and alumina will experience thermal fatigue after 10-20 cycles; RBSIC typically undergoes over 500 cycles before degradation.
3. The almost zero porosity provides airtightness for sealed combustion
A porosity of less than 0.1% means that the RBSIC tube is essentially airtight - the combustion gas inside the radiation tube cannot leak into the furnace atmosphere through the wall, and the furnace atmosphere cannot penetrate into the tube. This is crucial for radiation tubes in bright annealing, silicon steel, and non-ferrous metal heat treatment (where carbon or sulfur contamination can damage surface quality), as well as thermocouple sheaths in controlled atmosphere furnaces. Compared with recrystallized SiC (RSiC, 15-25% porosity) and nitride bonded SiC (NBSC, 10-15% porosity), RBSIC is essentially airtight, does not require coating, and can provide reliable sealing throughout its entire service life.
4. Free silicon phase achieves processability and reduces costs
The 8-12 vol% free silicon phase provides two practical benefits. Firstly, it enables RBSIC to be machined with standard hard alloy or even high-speed steel tools, unlike SSiC, alumina, and silicon nitride, which require diamond tools (5-10 times more expensive per machining hour). Customized modifications - trimming length, drilling, cutting flanges, precision machining end faces - can be carried out in standard mechanical workshops, and even on-site using portable tools. Secondly, lower manufacturing temperatures (1450-1700 ° C, SSiC at 2100 ° C+) and simpler processes have reduced raw material and energy costs by 40-60%. Overall effect: The cost of RBSIC tube is usually 50-60% of that of equivalent SSiC tube, while its performance below 1380 ° C is 80-90%, making it the most cost-effective high-performance ceramic tube in most industrial applications.

Applications

1. Heat treatment and industrial furnaces
The biggest application of RBSIC tube and pipes is as radiation heating tubes in industrial heat treatment furnaces. Gas radiation tubes are used for continuous annealing lines, galvanizing lines, bright annealing furnaces, carburizing furnaces, and sintering furnaces. In these furnaces, the combustion products must be isolated from the furnace atmosphere to protect product quality. RBSIC radiation tubes (straight, U-shaped, W-shaped, or P-type) operate at wall temperatures of 1000-1300 ° C and transfer heat through radiation. Compared with chromium nickel iron alloy or silicon carbide coated metal pipes, RBSIC has a 3-5 times longer lifespan (18-36 months vs. 6-12 months), a 15-25% increase in thermal efficiency, no metal contamination, and no need for protective atmosphere inside the pipe. RBSIC tubes are also used as muffle furnaces (stills) in batch furnaces for sintering powder metals, magnetic materials, and electronic ceramics.
2. Ceramic and advanced material manufacturing
In the ceramic industry, RBSIC tubes are used as kiln furniture - rollers, beams, and fixators - in roller kilns, tunnel kilns, and batch kilns for firing tableware, sanitary ware, technical ceramics, electronic components (MLCC, ferrite, PZT), and magnetic materials. RBSIC rollers can support vessels at temperatures up to 1300-1350 ° C. High temperature strength and low creep (strain<0.1% per 1000 hours at 1300 ° C and 20 MPa) ensure that the rollers remain straight, prevent deformation, and maintain consistent firing quality. Compared to aluminum oxide rollers (creep above 1200 ° C) and silicon nitride rollers (2-3 times more expensive), RBSIC provides the best performance cost ratio below 1350 ° C. RBSIC square tubes (beams) are used as structural supports for kiln car decks and intermittent kiln setups, carrying heavy stacking loads with minimal deflection.
3. Semiconductor, photovoltaic, and electronic manufacturing
In semiconductor and photovoltaic manufacturing, RBSIC tubes are used as process tubes and wafer boats in diffusion furnaces, oxidation furnaces, and LPCVD reactors at 900-1200 ° C. High purity (total metal impurities<100ppm, Fe<50ppm, Na<10ppm) ensures that the wafer will not be contaminated during high-temperature processing. Zero porosity can prevent process gas leakage and ensure uniform gas distribution. Compared to quartz tubes (which soften above 1150 ° C for 3-6 months), RBSIC tubes maintain dimensional stability at 1380 ° C for 2-5 years, reducing furnace downtime and cost per wafer. RBSIC is also used for wafer processing blades, pedestals, and chamber components in epitaxial and MOCVD reactors.

Technical data

Standard Tube Dimensions and Tolerances

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Why choose us?

1. Project based specification review
Silicon carbide pipes should be selected based on the actual transportation or heat treatment process, not just the nominal diameter. Before confirming product specifications, HUAO can review the required dimensions, operating temperature, medium, connection method, and installation environment.

2. Professional knowledge of reaction sintered silicon carbide
RBSiC components are used in demanding thermal and process environments, where common materials may require frequent replacement. HUAO focuses on silicon carbide components for industrial equipment and can discuss material configurations based on expected usage conditions.

3. Customized size
Industrial pipelines rarely follow a universal size. The diameter, wall thickness, length, opening, and connection details may vary depending on the project. We can manufacture according to customer requirements and provide drawings or detailed dimensions when quoting.

4. Suitable for multiple industries
Silicon carbide components are used in furnace equipment, chemical processing, metallurgy, petroleum related systems, boilers, and other industrial facilities. The correct design depends on the medium and operating environment, so application information will be considered during the specification confirmation process.

5. Material data available before purchase
Buyers can view key material information, including density, porosity, flexural strength, modulus of elasticity, thermal conductivity, and thermal expansion, before placing an order. This provides useful reference points for engineering teams when comparing project materials.

6. Complete RBSiC product capability
HUAO's current product range is not limited to pipelines. It also lists beams, Flat noodles, brackets, rollers, nozzles and profiled silicon carbide components. This can be useful when purchasing multiple refractory materials or kiln components for the same project.

7. Quality control of export orders
We conduct third-party testing before each shipment. For customers who purchase customized components, inspection requirements can be discussed together with technical drawings and order specifications.

FAQ

Q1: What is the difference between RBSIC and SSiC tubes, and which one should I choose?
A1: RBSIC (Reaction Bonded SiC, also known as SiSiC) is made by silicifying porous SiC carbon preforms at 1450-1700 ° C, forming a microstructure of SiC grains (85-90%) bonded by free silicon (8-12%). SSiC (pressureless sintered SiC) is produced by sintering ultrafine SiC powder with sintering aids at 2100 ° C+, resulting in a fully dense single-phase SiC microstructure. Advantages of RBSIC: Low cost (reduced by 40-60%), suitable for near net shape capability of large/complex pipes (length up to 2500 mm, outer diameter 300 mm), can be processed with hard alloy/HSS tools, and has good thermal shock resistance. The advantages of SSiC include higher strength (400-500 vs. 250-400 MPa), higher maximum operating temperature (1550 vs. 1380 ° C), better corrosion resistance (no free silicon phase, strong alkali resistance), and higher hardness. For applications below 1380 ° C, RBSIC is chosen because cost, size capability, and processability are important - radiation tubes, kiln furniture, universal thermocouple sheaths, wear-resistant tubes. For applications above 1380 ° C, in strongly alkaline environments, or requiring maximum strength and corrosion resistance, such as chemical process tubes, high-temperature thermocouple sheaths, and precision semiconductor components, please choose SSiC.
Q2: What is the maximum operating temperature for RBSIC tubes?
A2: In an oxidizing atmosphere (air, oxygen, carbon monoxide ₂, water vapor), the maximum continuous operating temperature is 1380 ° C. Above this temperature, the free silicon phase rapidly oxidizes (Si+O ₂ → SiO ₂), resulting in volume expansion, surface foaming, and reduced strength. In inert or reducing atmospheres (nitrogen, argon, hydrogen, vacuum), due to the inhibition of silicon oxidation, the maximum temperature can be extended to 1500-1600 ° C, but long-term exposure above 1400 ° C may lead to silicon evaporation and pore formation. For intermittent or cyclic operations, we recommend limiting the peak temperature to 1300 ° C to maximize service life. For applications that require continuous operation in an oxidizing atmosphere above 1380 ° C, SSiC or recrystallized SiC (RSiC) should be considered.
Q3: Can RBSIC tubes be processed or modified after delivery?
A3: Yes. Unlike SSiC, alumina, and silicon nitride that require diamond cutting tools, RBSIC can be machined with standard hard alloy cutting tools (in some cases high-speed steel cutting tools) because the free silicon phase acts as a machining lubricant. Common modifications include trimming the length to precise dimensions, drilling installation holes or thermocouple ports, cutting flanges or grooves, sealing facing the end face, tapering or reducing the cross-section, and creating perforation patterns. Water based coolant should be used for machining to prevent hot cracking, and the cutting speed should be moderate (50-100m/min for hard alloy tools). We can customize the processing at the factory before shipment, or provide pipes with additional processing allowance for on-site modification. For diamond machinable surface smoothness (Ra<0.8 μ m) or ultra precision dimensions, it is recommended to use diamond grinding.