| Customization: | Available |
|---|---|
| After-sales Service: | on-Line Service |
| Warranty: | 1 Years |
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Purpose:
The Corundum Furnace Tube is ingeniously designed to act as the inner lining of various experimental electric furnaces. It provides an exceptional barrier, isolating the delicate heating elements from the test materials while creating a secure enclosure for the heating zone. This versatile component is indispensable across industries, from high-temperature testing and analytical instruments to coal testing, metallurgical powder analysis, and the rigorous environments of chemical and glass laboratories.
Material & Manufacturing:
Crafted with precision from top-grade fused alumina, these Corundum Furnace Tubes are available in two specialized types:
Ultra-fine powder-bonded
Clay-bonded
Tailored to meet the unique demands of each user, specifications such as operating temperature, wear resistance, and chemical corrosion resistance are customizable to ensure optimal performance and longevity.
Dimensions:
Outer diameter: 15-200 mm
Length: 100-2000 mm
Wall thickness: 3-15 mm
Usage Guidelines:
To maximize efficiency when using high-temperature testing equipment, always ensure a gradual approach to heating and cooling This method minimizes internal stress caused by thermal expansion and contraction, effectively reducing the risk of cracking while enhancing the service life of the tube.
Composition:
Constructed from porous fused alumina, these crucibles offer unparalleled durability and remarkable heat resistance, standing up to the most demanding conditions.
Applications:
Perfectly suited for melting samples with weak alkaline fluxes (e.g., anhydrous NaCO).
Not suitable for strong alkaline fluxes (e.g., NaO, NaOH) or acidic fluxes (e.g., KSO), ensuring the safety and integrity of your testing processes.
99.70% Corundum
Max short-term temperature capability: 1800°C
Exhibits robust mechanical strength in both oxidizing and reducing atmospheres.
With high thermal conductivity and minimal thermal expansion, these crucibles ensure precision and efficiency in high-temperature applications.
Operating range: 1650-1700°C
Offers superior high-temperature insulation and
remains chemically inert to air, steam, hydrogen, carbon monoxide, etc., up to temperatures as high as 1700°C.
99.35% Corundum
Max short-term temperature capability: 1750°C
Operating range: 1600-1650°C
Demonstrates remarkable stability in both oxidizing and reducing atmospheres.
85.00% High-Alumina
Max short-term temperature capability: 1400°C
Operating range: 1290°C
Excels in providing good insulation and mechanical strength in environments with oxidizing and reducing atmospheres.
Features high thermal conductivity and low thermal expansion, ensuring reliability and efficiency.
Chemically inert to air, steam, hydrogen, carbon monoxide, etc., making these materials
ideal for a wide array of high-performance applications. Designed for enduring performance, our Low Noise Corundum Furnace Tube Crucible by RJ promises outstanding longevity. Perfectly operates under consistently stable temperature conditions, ensuring precise results.
Quartz glass tubes are a unique form of industrial technical glass crafted from high-purity silicon dioxide (SiO). Renowned for their exceptional durability and utility, quartz glass is celebrated for a remarkable suite of physical and chemical properties, such as:
Boasting a softening point around 1730°C,
these tubes are engineered for prolonged use at temperatures reaching 1100°C.
Short-term maximum capability peaks at: 1450°C,
Resiliently inert to nearly all acidic substances, excluding hydrofluoric acid (HF),it demonstrates unparalleled endurance.
Acid resistance is exponentially superior,
exceeding that of ceramics by 30× and outperforming stainless steel by
150×. This confers unmatched
high-temperature chemical stability, setting a new standardin engineering materials.
Exhibiting an exceptionally low thermal expansion coefficient,
it effortlessly withstands swift temperature shifts, such as heating to 1100°C and immediate quenching in water, without fracturing.
Providing superior optical clarity, it ensures excellent light transmission across the UV to infrared spectra,making it ideal for optical applications.
Visible light transmittance is measured at: >93%,
while UV spectrum transmittance reaches: Up to 80%+,
Boasting a resistivity that surpasses ordinary glass by 10,000×, it maintains exceptional insulation capabilities even at high temperatures.
Ensuring safety and reliability in demanding applications.
Usage & Properties
Engineered for use at elevated temperatures up to 1450°C, they are available inboth transparent and opaque variants to suit diverse needs. Advantages:
Combining high purity with outstanding temperature resilience, these crucibles support large sizes with precision engineering, ensuring superior thermal insulation, energy efficiency, and consistent quality. High purity, excellent temperature resistance, large size with high precision, good thermal insulation, energy-saving, and stable qualityfor consistently reliable results.
Chemical Compatibility
While not compatible with HF, these crucibles maintain their integrity against a wide range of chemicals.
However, at high temperatures, they may react with caustic alkalis and alkali metal carbonates,so caution is advised.
Suitable Fluxes
Perfectly suited for melting samples using KSO (potassium pyrosulfate) or KHSO (potassium bisulfate),these crucibles deliver consistent performance.
Additionally, they can be utilized with NaSO (sodium pyrosulfate, pre-dried at 212°C), making them versatile for various sample processing needs.
Quartz Crucible Usage & Maintenance
Comprised primarily of silicon dioxide (SiO), they are crafted for durability and reliability in the most demanding environments.
The Low Noise Corundum Furnace Tube Crucible by RJ showcases remarkable chemical inertness against most acids, excluding HF. However, it engages in reactions with caustic alkalis and alkali metal carbonates.
Experience unparalleled thermal stability with this state-of-the-art corundum furnace tube crucible, designed for exceptional performance.This innovative crucible can be heated directly over an open flame, offering versatile usage possibilities.
Delicate like fine glassware, this crucible requires gentle care.Its fragile nature demands meticulous handling to maintain its pristine condition.
Approved Flux Compatibility:
Utilize with permissible fluxes such as KHSO (potassium bisulfate), NaSO (sodium pyrosulfate, pre-dried at 212°C), achieving optimal results.
Boasting a maximum melting temperature of 800°C, it's perfect for high-temperature applications.
Essential Handling Precautions
With its brittle and fragile nature, caution is paramount.Handle with utmost care to avert breakage and ensure longevity.
Effective Cleaning Solutions
This crucible can be effortlessly cleaned using dilute inorganic acids, while avoiding HF, for a sparkling finish..
Material Characteristics Unveiled: Constructed to be incredibly hard and brittle, it withstands thermal shock and resists deformation at high temperatures, ensuring reliable performance. Other key physical properties include:
Density: 3.2 g/cm³, illustrating its robust and reliable structure.
Mohs Hardness: 9.5, providing superior durability.
Specific Heat: 0.17 kcal/kg·°C, optimizing thermal efficiency.
Thermal Conductivity: 20 kcal/m·h·°C, ensuring efficient heat transfer.
Linear Expansion Coefficient: 5×10 (m/°C), important for precise applications.
Silicon carbide rods exhibit unparalleled chemical stability. They resist acid attacks but can succumb to alkaline corrosion at elevated temperatures.
In prolonged usage above 1000°C, silicon carbide rods react with oxygen and water vapor through the following transformative processes:
SiC + 2O → SiO + CO, illustrating the gradual chemical evolution.
SiC + 4HO → SiO + 4H + CO, marking the intricacies of chemical reactions under heat.
Such reactions progressively increase the SiO content, heightening resistance and leading to aging over time.
Excessive water vapor accelerates SiC oxidation, whilst the generated H interacts with O to recreate HO, perpetuating a deleterious cycle and reducing rod lifespan.
The protective role of Nitrogen (N) in inhibiting SiC oxidation below 1200°C , yet it engages with SiC above 1350°C, leading to decomposition.
Chlorine (Cl): a potent agent that completely decomposes SiC, underlining the need for caution.
Fragility Awareness: Silicon carbide rods are distinguished by their hardness and brittleness-avoid jarring impacts or vibrations during transport and handling to maintain integrity.
Optimal Heating Zone Length: Ensure the heating section is perfectly aligned with the furnace chamber's width. Extending it into the furnace wall risks damaging the wall and compromising functionality.
Proper Cold End Length: The cold end should correspond to the furnace wall thickness plus an additional 50-150 mm of extension beyond the wall for efficient cooling and secure clamping.
Furnace Hole Diameter Specification: Should be precisely calculated for optimal performance and safety. 1.4-1.6× For optimal performance, ensure the cold end's outer diameter allows for thermal expansion. Tight holes or restrictive filler materials can lead to unwanted breakage. It's crucial to install rods in a way that accommodates this expansion. Experience unparalleled flexibility with our 360° rotation feature..
Spacing Requirements:
Maintain a safe distance to heated materials or the furnace wall of at least ≥ 3× the heating zone diameter.
Ensure center-to-center spacing between rods is not less than ≥ 4× the heating zone diameter.
Electrical Connection:Prevent increased contact resistance and potential cracking by ensuring proper connection.
Resistance Matching: Before use, carefully group rods with similar resistance valuesto ensure uniform performance.
Connections: For superior connectivity, use high-quality aluminum braids or foil to link cold ends to the main circuit. Be sure that all clamps are securely fastened.
Furnace Preheating: For optimal results, preheat new or long-idle furnaces using either old rods or alternative heat sources.
Storage: Store rods in a dry environment, as moisture negatively affects the aluminum layer of the cold ends.
Voltage Control: Utilize a voltage regulator. Start at 50% of the full operating voltage, gradually increasing to prevent thermal shock.
Operating Limits:
Optimize both surface load and temperature for efficient operation.
Max temperature: should not exceed ≤1650°C.
Prevent any chemical reactions in environments containing corrosive gases.
Replacement: When necessary, replace rods with those of similar resistance or consider replacing the entire set. Partially used rods can be reused at a later time if their resistance values are still suitable.
Avoid Molten Metal: Contact with molten metal can result in breakage.
Avoid Alkalis: Exposure to alkali metals and oxides can corrode the rods, compromising their integrity.
Regular Checks: Consistently monitor amperage, voltage, and temperature. Inspect for possible issues such as:
Loose or oxidized clamps,
rod fractures,
and 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 high-temperature oxidizing environments, silicon molybdenum rods form a durable quartz (SiO) layer on their surface that effectively prevents further oxidation. Should the element temperature exceed 1700°C, this protective quartz layer melts. However, continued use in oxidizing atmospheres will allow for the regeneration of this crucial quartz layer.
Important Note: Take caution! Silicon molybdenum rods are not suited for prolonged use in the 400-700°C range. Operating in this temperature window can lead to low-temperature oxidation, gradually transforming the element into a fragile powder form.
| 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 experience a slight softening phenomenon at elevated temperatures exceeding 1500°C. However, they exhibit increased hardness and brittleness at lower temperatures. To effectively mitigate thermal stress and accommodate the natural expansion and contraction due to temperature fluctuations, employ a free-hanging vertical installation approach. This installation technique not only reduces stress but also allows for hot replacement of rods, eliminating the need for complete furnace cooldown.
Furnace Lining Material
Choose corundum bricks that have FeO content <1%. An elevated FeO concentration reacts negatively with the SiO protective layer, producing low-melting silicates that expedite rod wear.
Cold-End Sealing
Hot gas emissions from cold ends increase thermal loss and may potentially damage conductive clamps and leads. Opt for asbestos clamps as the preferred choice for insulation purposes.
Handling Fragility
Si-Mo rods possess brittleness and have low resistance to flexural stress. Exercise caution to avoid impacts during installation.
Secure asbestos or ceramic clamps before attaching conductive straps. Refrain from over-tighteningto preserve integrity.
Mounting with Insulating Bricks
Employ foamed corundum split bricks to enclose rods, easing mechanical stress through installation and removal processes.
Furnace Roof Installation
Place rod-mounted bricks into the dedicated pre-cut slots in the furnace roof. Ensure bricks extend beyond the roof surface to facilitate smoother disassembly.
Conductive Strap Connection
Attach straps safely to the pre-installed brackets. Avoid unnecessary tension or awkward bends to prevent undue stress.
Anti-Sagging Measure
Utilize refractory mortar, based on water glass, to secure joints and firmly anchor asbestos clamps, countering sagging from thermal expansion.
Positioning Clearances
Heating zone taper: Maintain a distance of 25-30 mm from the furnace walls to ensure safety.
Cold ends: Extend 75 mm above the furnace roof for optimal performance.
Lower heating end: Ensure a minimal clearance of50 mm from the furnace floor for safe operation.
Spacing Between Rods
Ensure that the center-to-center distance meets or exceeds the specified rod spacing requirements.
Gravity Balance
Expertly engineered balance weight distribution at both the cold ends and wiring components, meticulously designed to prevent any bending of the crucial heating section.
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