| Customization: | Available |
|---|---|
| After-sales Service: | on-Line Service |
| Warranty: | 1 Years |
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Purpose:
The corundum furnace tube is an indispensable component, serving as the inner lining for various high-precision experimental electric furnaces. Its primary role is to effectively isolate the heating elements from the test materials, creating a controlled environment by enclosing the heating zone and securely holding the test substances. This essential feature makes it highly sought after in high-temperature testing and analytical instruments across numerous industries, including coal testing, metallurgical powder analysis, and sophisticated chemical and glass laboratory equipment.
Material & Manufacturing:
Expertly crafted from high-quality fused alumina, these corundum furnace tubes are available in two distinguished types:
Ultra-fine powder-bonded
Clay-bonded
Our specifications are meticulously customized to meet the unique requirements of our clients, including considerations for operating temperature, wear resistance, and chemical corrosion resistance, ensuring optimal performance.
Dimensions:
Outer diameter ranges from: 15-200 mm
Length varies between: 100-2000 mm
Wall thickness can be: 3-15 mm
Usage Guidelines:
While utilizing high-temperature testing equipment, it is imperative to ensure gradual heating and cooling to effectively minimize internal stress caused by thermal expansion and contraction. This essential practice significantly reduces the risk of cracking, thereby extending the tube's service life.
Composition:
Composed of porous fused alumina, which guarantees exceptional durability and superior heat resistance.
Applications:
Ideally suited for melting samples when using weak alkaline fluxes (e.g., anhydrous NaCO).
However, it is not recommended for strong alkaline fluxes (e.g., NaO, NaOH) or acidic fluxes (e.g., KSO), as these can be detrimental.
99.70% Corundum
Max short-term temperature withstands up to: 1800°C
Exhibits remarkable mechanical strength within oxidizing/reducing atmospheres.
Boasting high thermal conductivity and minimal thermal expansion.
Operating range comfortably between: 1650-1700°C
Delivers excellent high-temperature insulation &
remains chemically inert to air, steam, H, CO, etc., up to a robust 1700°C.
99.35% Corundum
Max short-term temperature achievable: 1750°C
Operating range effectively spans: 1600-1650°C
Maintains stable performance even in oxidizing/reducing atmospheres.
85.00% High-Alumina
Max short-term temperature capability: 1400°C
Operating range ideally at: 1290°C
Offers reliable insulation & mechanical strength within oxidizing/reducing atmospheres.
Features high thermal conductivity while ensuring low thermal expansion.
Chemically inert to air, steam, H, CO, etc.
Suitable for ensures reliable performance over extended periods even when subjected to consistent temperature environments.
Quartz glass tubes are crafted from pure silicon dioxide (SiO), rendering them a specialized industrial material with exceptional characteristics. This remarkable glass variety boasts a suite of extraordinary physical and chemical properties, such as:
Softening point at a staggering temperature of approximately 1730°C
Sustained use: Capable of enduring temperatures up to 1100°C
Maximum short-term exposure: 1450°C
Virtually inert to all acidic substances except hydrofluoric acid (HF).
Acid resistance level:
30 times greater than that of traditional ceramics
and 150 times greater than that of stainless steel.
Exhibits superior chemical stability at elevated temperatures, a feature unmatched by other engineering materials available.
Boasts an extremely low thermal expansion coefficient.
Can endure rapid temperature fluctuations (e.g., safely being heated to 1100°C and immediately quenched in room-temperature water without the risk of cracking).
Offers excellent light transmission properties across the ultraviolet through infrared spectra.
Visible light transmittance measures: greater than 93%
While UV spectrum transmittance is: an impressive 80% or more
Resistivity is measured at: 10,000 times higher than that of ordinary glass.
Sustains its exceptional insulating properties even at elevated temperatures.
Utilization & Attributes
Capable of usage at temperatures up to 1450°C,available in both transparent and opaque forms.
Key Advantages: Highly pure, superb temperature resistance, available in large sizes with precision, delivers excellent thermal insulation, energy-efficient, consistently stable quality.
Chemical Compatibility Factors
Incompatible with hydrofluoric acid (HF) .
At higher temperatures, it readily reacts with caustic alkalis and alkali metal carbonates.
Suitable Melting Agents
Ideal for sample melting using potassium pyrosulfate (KSO) or potassium bisulfate (KHSO).
Additionally, it is compatible with sodium pyrosulfate (NaSO), provided it is pre-dried at 212°C, for seamless sample processing.
Comprehensive Quartz Crucible Usage & Maintenance
Its primary chemical composition is predominantly silicon dioxide (SiO).
Our SiC Heating Rods are marvels of chemical resilience, remaining unaffected by most acids, with the exception of HF. However, they can react with caustic alkalis and alkali metal carbonates, showcasing their distinctive interaction profile.
Boasting unparalleled thermal stability, these rods are designed to excel in high-temperature environments, ensuring consistent performance and longevity.Ingeniously crafted, our SiC Heating Rods can be directly heated over an open flame, offering unmatched versatility in various applications.
Despite their exceptional capabilities, these rods are fragile, much like fine glassware, and require delicate handling to maintain their integrity.Their delicate nature mandates careful handling to prevent any accidental damage, ensuring they continue to perform flawlessly.
Our rods are compatible with an array of permissible fluxes, enhancing their usability.:
These include KHSO (potassium bisulfate) and NaSO (sodium pyrosulfate, pre-dried at 212°C), providing flexibility in usage.
Engineered to endure high temperatures, they boast a maximum melting temperature of 800°C, making them suitable for demanding applications.
Handling Precautions
Due to their brittle and fragile nature, special care must be taken during handling to avoid breakage and ensure longevity.Handle these rods with the utmost care to protect them from damage and to maintain their high-performance standards.
Cleaning
For maintenance, they can be effectively cleaned using dilute inorganic acids, avoiding HF to maintain their pristine condition..
Material Characteristics: Possessing a hard and brittle nature, these rods are resistant to thermal shock and retain their form at elevated temperatures. Key physical properties include:
An impressive density of 3.2 g/cm³, highlighting their robust composition.
An outstanding Mohs Hardness of 9.5, demonstrating exceptional durability.
Specific Heat capacity of 0.17 kcal/kg·°C, facilitating efficient thermal management.
Thermal Conductivity of 20 kcal/m·h·°C, ensuring optimal heat transfer.
Linear Expansion Coefficient of 5×10 (m/°C), providing stability during temperature fluctuations.
Silicon carbide rods showcase remarkable chemical stability, particularly resistant to acidic environments, yet they may succumb to alkaline corrosion at elevated temperatures.
When subjected to prolonged usage above 1000°C, these rods react with oxygen and water vapor, resulting in:
SiC + 2O → SiO + CO, a crucial reaction to be mindful of in specific conditions.
SiC + 4HO → SiO + 4H + CO, further emphasizing the need for controlled environments.
These interactions gradually augment the SiO content within the rods, consequently elevating resistance and promoting aging.
Excess water vapor expedites SiC oxidation, with the ensuing H interacting with O to regenerate HO, initiating a detrimental cycle that curtails the rods' lifespan.
Nitrogen (N) aids in curbing SiC oxidation below 1200°C yet reacts with SiC beyond 1350°C, leading to its decomposition.
Chlorine (Cl) induces complete decomposition of SiC, necessitating cautious application.
Fragility: Despite their robust nature, silicon carbide rods are inherently brittle-avoid applying excessive force or subjecting them to vibrations during transport and use.
Heating Zone Length: Ensure the heating zone aligns perfectly with the furnace chamber's width. Overextension into the furnace wall may compromise its structural integrity.
Cold End Length: Design the cold end to match the furnace wall thickness, adding 50-150 mm beyond the wall to facilitate cooling and secure clamping.
Furnace Hole Diameter: Should be carefully considered to ensure optimal performance and compatibility with our rods. 1.4-1.6× The cold end's outer diameter must be considered carefully. Using tight holes or filler materials can impede the thermal expansion process, potentially leading to breakage. Thus, it's crucial to install the rods in a way that allows 360° rotation.
Spacing Requirements:
Ensure ideal spacing for optimal performance. Distance to heated materials or furnace wall should be maintained at a minimum of 3× the diameter of the heating zone.
Also, ensure the center-to-center spacing between rods is at least 4× the diameter of the heating zone.
Electrical Connectior: Improper connections can increase contact resistance and heighten the risk of cracking.
Resistance Matching: Before initial use, it is vital to group rods that showcase similar resistance valuesto ensure uniform performance.
ns: Use aluminum braids or foil to connect the cold ends to the main circuit. Tight, secure clamps are essential.
Furnace Preheating: For new or long-idle furnaces, initiate preheating using old rods or other heat sources to ensure optimal starting conditions.
Storage: Store rods in a dry environment. Moisture can severely degrade the aluminum layer at the cold end.
Voltage Control: For voltage regulation, begin with 50% of the standard operating voltage, and gradually increase to full capacity to prevent thermal shock.
Operating Limits:
Optimize surface load and temperature for efficiency.
Maximum temperature capacity: ≤1650°C.
Avoid exposure to corrosive gas environments to prevent chemical reactions.
Replacement: When necessary, replace rods with ones of similar resistance or consider replacing the entire set. Partially used rods may be reused later if their resistance remains suitable.
Avoid Molten Metal: Contact with molten metal is detrimental and leads to breakage.
Avoid Alkalis: Alkali metals and oxides are corrosive to the rods.
Regular Checks: Regularly monitor amperage, voltage, and temperature. Conduct inspections for:
Loose or oxidized clamps,
Fractures in rods,
Uneven heating, identifiable by red-hot zones.
| Property | Value |
|---|---|
| Bulk Density | 5.5 g/cm³ |
| Flexural Strength | 15-25 kg/cm² |
| Vickers Hardness | (HV) 570 kg/mm² |
| Porosity | 7.4% |
| Water Absorption | 1.2% |
| Thermal Elongation | 4% |
In high-temperature oxidizing atmospheres, silicon molybdenum rods develop a protective quartz (SiO) layer, preventing further oxidation. At temperatures surpassing 1700°C, this quartz layer melts, but it regenerates with continued use in oxidizing conditions, ensuring prolonged protection.
Important Note: Silicon molybdenum rods should not be used long-term in the 400-700°C range, as low-temperature oxidation will cause the element to deteriorate into powder form. Protect your investment by avoiding prolonged exposure within this temperature margin to maintain the structural integrity and longevity of your Si-Mo rods.
| Atmosphere | Continuous Use Temp. | Short-term Max Temp. |
|---|---|---|
| NO, CO, O, Air | 1700°C | 1800°C |
| He, Ar, Ne | 1650°C | 1750°C |
| SO | 1600°C | 1700°C |
| CO, N | 1500°C | 1600°C |
| Moist H | 1400°C | 1500°C |
| Dry H | 1350°C | 1450°C |
Silicon molybdenum (Si-Mo) rods exhibit slight softening at high temperatures (above 1500°C) but become hard and brittle at low temperatures. To minimize thermal stress and accommodate thermal expansion/contraction, a strategic installation is crucial. Consider a free-hanging vertical installation is recommended. This method also facilitates seamless hot replacement of rods without waiting for furnace cooling. Swift maintenance keeps operations running smoothly.
Furnace Lining Material: Select the best materials to protect and enhance your heating elements.
Use corundum bricks with FeO content <1%. Higher FeO reacts with the protective SiO layer, forming low-melting silicates that accelerate rod degradation. This ensures a robust and secure environment for your rods.
Cold-End Sealing: Preserve the integrity of the cold ends of your rods with effective sealing techniques.
Hot gas leakage from cold ends increases heat loss and may damage conductive clamps/leads. Prevent these issues by using asbestos clamps are preferred for insulation, maintaining efficiency and safety.
Handling Fragility: Handle with care to ensure the longevity and optimum performance of your Si-Mo rods.
Si-Mo rods are brittle with low flexural strength. Avoid impacts during installation to keep them in pristine condition.
Secure asbestos/ceramic clamps before connecting conductive straps to ensure a stable and reliable setup. Do not overtighten. Gentle handling during installation will prevent damage and ensure lasting performance.
Mounting with Insulating Bricks: Ensure your rods are well-supported and insulated for maximum efficiency.
Use foamed corundum split bricks to house rods, minimizing mechanical stress during installation/removal. This creates a safe and durable environment for your equipment.
Furnace Roof Installation: Proper installation techniques ensure efficient operation and easy maintenance.
Insert rod-mounted bricks into pre-cut furnace roof slots. This ensures an ergonomic and straightforward setup. Extend bricks beyond the roof surface for easier disassembly. Such thoughtful planning facilitates effortless maintenance.
Conductive Strap Connection: Establish secure and effective electrical connections.
Connect straps to pre-installed brackets. Ensure a smooth and tension-free connection for optimal performance. Avoid tension or unnatural bends to prevent stress. This ensures the longevity of your straps and overall system integrity.
Anti-Sagging Measure: Maintain the structural integrity of your system with strategic countermeasures.
Apply refractory mortar (water glass-based) to joints, fixing asbestos clamps firmly to counter thermal expansion-induced drooping. This measure ensures a stable and consistent operation.
Positioning Clearances: Ensure sufficient space for efficient heat distribution and safety.
Heating zone taper: Maintain 25-30 mm from furnace walls to optimize heat flow and protection.
Cold ends: Extend 75 mm above the furnace roof to facilitate easy handling and maintenance.
Lower heating end: Keep ≥50 mm from the furnace floor for effective heat distribution and protection.
Spacing Between Rods: Ensure adequate spacing to enhance operational efficiency.
Ensure Ensure precise and optimal center-to-center distance with our rod spacing specifications that guarantee unparalleled performance..
Experience the perfect harmony of innovation with our Gravity Balance feature, designed to enhance stability and efficiency.
Meticulously engineered balance weight distribution at both cold ends and critical wiring parts, to effectively prevent any bending of the heating section, ensuring longevity and reliability.
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