| Customization: | Available |
|---|---|
| After-sales Service: | on-Line Service |
| Warranty: | 1 Years |
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Purpose:
The versatile furnace tube functions as the essential inner lining for a wide range of experimental electric furnaces. Its primary roles include isolating heating elements from test materials, enclosing the crucial heating zone, and securely holding the test substances. It finds extensive application in high-temperature testing and analytical instruments across diverse industries such as coal testing, metallurgical powder analysis, and chemical/glass laboratory equipment.
Material & Manufacturing:
Corundum furnace tubes are expertly crafted from high-quality fused alumina, available in two distinct types:
Ultra-fine powder-bonded, ensuring superior performance and longevity.
Clay-bonded for enhanced durability and reliability.
Specifications are tailored precisely to meet user requirements, taking into account factors such as operating temperature, wear resistance, and chemical corrosion resistance.
Dimensions:
Outer diameter: 15-200 mm, providing a wide range of options.
Length: 100-2000 mm, versatile enough to meet various applications.
Wall thickness: 3-15 mm, designed for optimal strength and integrity.
Usage Guidelines:
When employing high-temperature testing equipment, it is crucial to ensure gradual heating and cooling, to minimize internal stresses caused by thermal expansion and contraction. This practice significantly reduces the risk of cracking, thereby extending the tube's service life.
Composition:
Crafted from porous fused alumina, this material offers unparalleled durability and heat resistance.
Applications:
Ideal for melting samples when utilizing weak alkaline fluxes (e.g., anhydrous NaCO), ensuring exceptional reliability.
Not suitable for use with strong alkaline fluxes (e.g., NaO, NaOH) or acidic fluxes (e.g., KSO), ensuring safe and precise operations.
99.70% Corundum ensures high-end performance.
Max short-term temperature: 1800°C, providing robust heat handling capabilities.
Maintain excellent mechanical strength in oxidizing and reducing atmospheres, assuring reliability and safety.
Offers high thermal conductivity with low thermal expansion.
Operating range: 1650-1700°C, ensuring consistent performance.
Provides excellent high-temperature insulation and
remains chemically inert to air, steam, H, CO, etc., up to 1700°C.
99.35% Corundum for reliable quality.
Max short-term temperature: 1750°C, suitable for demanding applications.
Operating range: 1600-1650°C, for versatile usage.
Stably performs in oxidizing and reducing atmospheres, ideal for various conditions.
85.00% High-Alumina composition.
Max short-term temperature: 1400°C, suited for less extreme temperature needs.
Operating range: 1290°C, ensuring efficiency.
Provides good insulation and mechanical strength in oxidizing and reducing atmospheres, adaptable to varied environments.
Features high thermal conductivity with low thermal expansion.
Chemically inert to air, steam, H, CO, etc.
Suitable for long-term use under stable temperature conditions.
Quartz glass tubes are a specialized industrial technical glass made from silicon dioxide (SiO), serving as an exceptional fundamental material. Quartz glass exhibits a series of outstanding physical and chemical properties, including:
Softening point: ~1730°C
Long-term use: Up to 1100°C
Short-term maximum: 1450°C
Nearly inert to all acids except (HF).
Acid resistance:
30× that of ceramics
150× that of stainless steel
Superior high-temperature chemical stability, unmatched by other engineering materials.
Extremely low thermal expansion coefficient.
Withstands rapid temperature changes (e.g., heating to 1100°C and quenching in room-temperature water without cracking).
Excellent light transmission across UV to infrared spectra.
Visible light transmittance: >93%
UV spectrum transmittance: Up to 80%+
Resistivity: 10,000× higher than ordinary glass.
Maintains superb insulation even at high temperatures.
Usage & Properties
Can be used up to 1450°C, available in transparent and opaque variants.
Advantages: High purity, excellent temperature resistance, large size with high precision, good thermal insulation, energy-saving, and stable quality.
Chemical Compatibility
Not compatible with HF .
At high temperatures, reacts easily with caustic alkalis and alkali metal carbonates.
Suitable Fluxes
Ideal for melting samples using KSO (potassium pyrosulfate) or KHSO (potassium bisulfate).
Can also be used with NaSO (sodium pyrosulfate, pre-dried at 212°C) for sample processing.
Quartz Crucible Usage & Maintenance
Primary chemical composition: Composed primarily of high-purity Silicon dioxide (SiO), this exceptional material ensures unrivaled performance in demanding laboratory environments.
Chemically inert to most acids, except the highly reactive HF. However, it showcases remarkable resistance against caustic alkalis and alkali metal carbonates, making it an invaluable asset for a myriad of scientific applications.
Excellent thermal stability: Its outstanding ability to withstand high thermal variations ensures safety and reliability during extensive experimental procedures.-can be heated directly over a flame, providing incredible versatility in laboratory operations and research.
Fragile like glassware: Handle with the same care as fine glass to maintain its integrity and functionality.-requires careful handling to prevent breakage, ensuring its long-term utility and performance.
Permissible fluxes: Utilize with confidence in experimental setups.:
KHSO (potassium bisulfate), NaSO (sodium pyrosulfate, pre-dried at 212°C), etc., for optimized chemical interactions in your work.
Maximum melting temperature: Withstands up to 800°C, accommodating a wide range of laboratory heating requirements.
Handling Precautions: Essential guidelines to maximize lifespan and efficiency.
Brittle and fragile: It demands meticulous care to avoid damage and ensure continued effectiveness.-handle with care to avoid breakage, preserving its pristine condition.
Cleaning: Essential practices for maintaining purity and performance.
Can be cleaned with: Follow these instructions to uphold product integrity. dilute inorganic acids (except HF), ensuring the material's longevity and cleanliness..
Material Characteristics: Explore the robust features of this remarkable composition: Hard and brittle, renowned for its incredible resistance to thermal shock and its impressive stability at soaring temperatures. Other outstanding physical properties include:
Density: 3.2 g/cm³, exemplifying its solid structure and robustness.
Mohs Hardness: 9.5, indicative of its supreme scratch resistance and durability.
Specific Heat: 0.17 kcal/kg·°C, facilitating efficient thermal management.
Thermal Conductivity: 20 kcal/m·h·°C, a testament to its superior heat dissipation capabilities.
Linear Expansion Coefficient: 5×10 (m/°C), demonstrating its exceptional thermal stability.
Silicon carbide rods exhibit excellent chemical stability and unsurpassed resistance to acids, ensuring longevity. However, they can be susceptible to corrosion by alkaline substances at elevated temperatures.
When used long-term above: Discover the reactions at: 1000°C, silicon carbide rods react with oxygen and water vapor as follows, impacting performance:
SiC + 2O → SiO + CO: A reaction that gradually alters the composition.
SiC + 4HO → SiO + 4H + CO: Further transformations that necessitate careful monitoring.
These reactions gradually increase the SiO content in the rod, leading to higher resistance and aging, influencing its operational lifespan.
Excessive water vapor accelerates SiC oxidation, and the produced H reacts with O to form HO again, creating a harmful cycle that shortens the rod's lifespan. Mitigation is essential to maintain functionality.
Nitrogen (N): A protective agent at lower temperatures. prevents SiC oxidation below: Experience stability up to: 1200°C but reacts with SiC above: Beyond which, observe changes at: 1350°C, decomposing it. This critical threshold underscores the importance of controlled conditions.
Chlorine (Cl): A reactive agent. completely decomposes SiC, highlighting a significant consideration for usage.
Fragility: Recognize the delicate nature of silicon carbide rods. Silicon carbide rods are hard and brittle-avoid strong impacts or vibrations during transport and handling to preserve their condition and performance.
Heating Zone Length: Optimal configuration for efficiency. The heating section should match the furnace chamber's width. Extending it into the furnace wall may damage the wall, a crucial consideration for setup.
Cold End Length: Ensure suitable adjustments for effective operation. The cold end should equal the furnace wall thickness plus 50-150 mm of extension outside the wall for cooling and clamping, ensuring optimal performance.
Furnace Hole Diameter: A critical specification for compatibility and efficiency in your applications. Ensure to maintain an appropriate spacing and avoid restrictions that may impede thermal expansion. 1.4-1.6× the cold end's outer diameter. Any tight holes or use of filler materials can hinder thermal expansion, potentially leading to breakage. When installing rods, ensure proper allowance is made for thermal movement. 360° rotation.
Spacing Requirements:
Distance to heated materials or furnace wall should be no less than 3× the diameter of the heating zone.
Maintain a center-to-center spacing between the rods of no less than 4× the diameter of the heating zone.
Electrical Connection:Avoid increasing contact resistance and the potential risk of cracking.
Resistance Matching: Prior to operation, group rods having similar resistance valuesfor optimal performance.
Connections: Employ high-quality aluminum braids or foil to securely connect the cold ends to the main circuit. Ensure clamps are fastened tightly.
Furnace Preheating: When preheating new or long-idle furnaces, use older rods or alternative heat sources to initiate the process.
Storage: Store rods in a dry environment as moisture can deteriorate the cold end's protective aluminum layer.
Voltage Control: Utilize a reliable voltage regulator. Begin with 50% of the operating voltage and gradually increase to prevent thermal shock.
Operating Limits:
Surface load and temperature should be meticulously optimized for safe operation.
Maximum temperature threshold: ≤1650°C.
Refrain from chemical interactions in environments containing corrosive gases.
Replacement: When replacing, opt for rods with similar resistance or consider replacing the entire set. Partially used rods can be reused if their resistance remains suitable.
Avoid Molten Metal: Contact with molten metal should be avoided as it can cause breakage.
Avoid Alkalis: Exposure to alkali metals and oxides should be prevented to avoid corrosion of the rods.
Regular Checks: Continuously monitor amperage, voltage, and temperature. Inspect for issues such as:
Loose or oxidized clamps,
Fractured rods,
Uneven heating, indicated 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 the demanding environments of high-temperature oxidizing atmospheres, silicon molybdenum rods reveal their resilience by forming an extraordinary protective quartz (SiO) layer on their surface, effectively shielding against further oxidation. However, when the ambient element temperature surpasses 1700°C, this remarkable quartz layer begins to melt. Yet, fear not, as with continued usage in oxidizing atmospheres, the protective quartz layer masterfully regenerates itself, ensuring sustained performance.
Important Note: It is crucial to refrain from utilizing silicon molybdenum rods over prolonged periods within the 400-700°C temperature range. At these lower temperatures, oxidation can cause the rods to deteriorate significantly, transforming them into a powdery form, which compromises the integrity and functionality of the elements.
| 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 display a fascinating behavior of slight softening when exposed to high temperatures exceeding 1500°C. Yet, they become hard and brittle in cooler conditions. To effectively manage thermal stress and accommodate the natural expansion and contraction that occurs with temperature changes, it is advisable to adopt a free-hanging vertical installation approach. This innovative method not only manages stress but also allows for the hot replacement of rods, eliminating the need to wait for the furnace to cool down.
Furnace Lining Material
Use corundum bricks with FeO content <1%. This is critical as higher levels of FeO interact with the protective SiO layer, forming low-melting silicates that can accelerate the degradation of the rods.
Cold-End Sealing
Preventing hot gas leakage from cold ends is essential, as it can lead to increased heat loss and potential damage to conductive clamps and leads. Asbestos clamps are ideal for superior insulation, offering a reliable solution.
Handling Fragility
Si-Mo rods are brittle with inherently low flexural strength, so it is vital to handle them with care and avoid impacts during installation.
Secure asbestos/ceramic clamps properly before connecting conductive straps, ensuring they are firmly in place. Do not overtightenas this could lead to damage.
Mounting with Insulating Bricks
Use foamed corundum split bricks to house rods, which helps in minimizing mechanical stress during the installation and removal processes.
Furnace Roof Installation
Carefully insert rod-mounted bricks into specially designed pre-cut slots in the furnace roof. These bricks should extend beyond the surface of the roof to facilitate easier disassembly when required.
Conductive Strap Connection
Connect straps effectively to pre-installed brackets. Ensure that there is no tension or unnatural bending to avert undue stress and potential damage.
Anti-Sagging Measure
Apply refractory mortar (water glass-based) to joints, providing a firm fixation of asbestos clamps to counteract thermal expansion-induced sagging.
Positioning Clearances
Heating zone taper: Maintain a strategic clearance of 25-30 mm from the furnace walls.
Cold ends: Ensure they extend a minimum of 75 mm above the furnace roof to allow for optimal performance.
Lower heating end: Maintain a distance of at least50 mm from the furnace floor to ensure optimal performance.
Spacing Between Rods
Ensure that the center-to-center distance is greater than or equal to the rod spacing specificationsto achieve structural integrity.
Gravity Balance
Balance the weight distribution meticulously at both cold ends and wiring parts to effectively prevent any bending of the heating section and ensure long-lasting durability.
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