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20–25mm Pressureless Sintered SiC Thermocouple Protection Tubes

Basic Properties
Place of Origin: Китай
Brand Name: KEGU
Model Number: Настраиваемый
Trading Properties
Minimum Order Quantity: Возможен торг
Price: Подлежит обсуждению
Payment Terms: LC,D/A,D/P,T/T,Western Union,MoneyGram
Резюме продукта
20–25mm Pressureless Sintered SiC Thermocouple Protection TubesProduct OverviewDesigned for harsh high-temperature and corrosive environments including coal gasifiers, hot blast stoves, non-ferrous metal smelting, and sulfuric acid concentration plants. The 25mm OD / 20mm ID configuration with 2.5mm ...

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Sintered SiC Thermocouple Protection Tubes

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25mm Sintered SiC Thermocouple Protection Tubes

Характер продукции
20–25mm Pressureless Sintered SiC Thermocouple Protection Tubes
Product Overview

Designed for harsh high-temperature and corrosive environments including coal gasifiers, hot blast stoves, non-ferrous metal smelting, and sulfuric acid concentration plants. The 25mm OD / 20mm ID configuration with 2.5mm wall thickness balances mechanical strength and thermal response time, establishing it as the industrial standard size.

SpecificationOD (mm)ID (mm)Wall Thickness (mm)Typical Length (mm)
Mainstream type25202.5900–950
Key Performance Parameters
ParameterValueUnit
SiC content≥98wt%
Density≥3.10g/cm³
Apparent porosity0vol%
Flexural strength400–550MPa
Compressive strength>2500MPa
Thermal conductivity (25°C)120–270W/(m·K)
Coefficient of thermal expansion (25–500°C)3.8*10⁻⁶/K
Max. service temperature (oxidizing)1600–1750°C
Max. service temperature (protective atmosphere)1900–2000°C
Manufacturing Process: Cold Isostatic Pressing + Pressureless Sintering
Cold Isostatic Pressing (wet-bag method)
  • Pressure: 150–300 MPa, isostatic (uniform in all directions)
  • Green relative density: 55%–62%
  • Advantages: Uniform wall thickness (deviation ≤0.2mm), no density gradient, smooth inner bore, length-to-diameter ratio >20:1, no post-sintering distortion
Pressureless Sintering (solid-state sintering, B+C additives)
  • Temperature: 2020–2220°C under argon or vacuum
  • Achieved density: >98% (near fully dense)
  • Characteristics: Clean grain boundaries, no free silicon, stable high-temperature performance
Comparison: SSiC vs. Reaction-Bonded SiC (RBSiC)
PropertySSiC (pressureless sintered)RBSiC (reaction-bonded)
SiC content≥98%~82%
Free siliconNone~17%
Max. service temperature1650–1750°C<1400°C (free silicon melts)
Flexural strength400–550 MPa250–350 MPa
Resistance to strong acids/basesExcellentPoor
Density (apparent porosity)0% porosityOpen porosity present
Core Technical Advantages
  • Ultra-high temperature resistance: Long-term use at 1600–1750°C in oxidizing atmospheres
  • High thermal conductivity: 270 W/(m·K), 4–5 times that of alumina
  • Outstanding thermal shock resistance: Low CTE (3.8*10⁻⁶/K), withstands 300°C/min thermal shock
  • Strong corrosion resistance: Insoluble in hydrochloric acid, sulfuric acid, molten aluminum/zinc
  • High mechanical strength: Flexural strength ≥400 MPa, compressive strength ≥2500 MPa
  • Fully dense and gas-tight: Zero porosity prevents corrosive gas penetration
  • CIP-enabled dimensional precision: Uniform wall thickness, straightness ≤0.5 mm/m, no deformation of thin-walled tubes
Typical Applications
IndustrySpecific ApplicationTemperature Range
ChemicalCoal gasifiers, sulfuric acid concentration towers1200–1650°C
MetallurgicalMolten aluminum/copper/zinc bath temperature measurement700–1700°C
Iron & SteelHot blast stove domes, continuous casting1000–1500°C
KilnsCement rotary kilns, glass melting furnaces900–1600°C
Supplementary Information
Installation & Sealing Recommendations
  • Use a loose flange or flexible graphite gasket seal; avoid rigid connections that may induce thermal stress cracking
  • Leave a 3–5 mm expansion gap between the protection tube and furnace wall; the tube bottom must not contact internal furnace components
Comparison with Other Common Thermocouple Protection Tube Materials
MaterialMax. Service Temp (°C)Acid/Alkali ResistanceThermal Shock ResistanceCostSuitable Application
SSiC (this product)1750ExcellentExcellentHigh>1400°C, strong corrosion
Alumina (99%)1600GoodFairMediumClean atmospheres, mild acids/alkalis
Metal alloy (e.g., Inconel)1100PoorGoodMedium–HighLow temperature, reducing atmospheres
Fused silica1100Not alkali-resistantExcellentLowShort-term, low-temperature measurements
Service Life & Reliability
  • Under continuous use at 1600°C in oxidizing atmospheres, design life is 2–5 years, 5–10 times longer than high-temperature alloy tubes
  • CIP-formed tubes, free from internal defects, exhibit a first-year failure probability <0.1%
  • Main failure modes: thermal shock-induced through-cracks (70%), mechanical impact damage (20%), alkali attack (10%)
Customization & Certifications
  • Available lengths: 200–1500 mm; ODs from 15–60 mm; ID tolerance after grinding: ±0.05 mm
  • Compatible flange materials: 304, 316L, Hastelloy; sealing faces: flat, raised, tongue-and-groove
  • Compliant with ASTM C1793 (Standard for Pressureless Sintered Silicon Carbide) and GB/T 25942-2010
Summary

The 25*20mm pressureless sintered SiC (SSiC) thermocouple protection tube, manufactured by cold isostatic pressing (CIP) followed by pressureless sintering, delivers exceptional high-temperature capability, strong corrosion resistance, high thermal conductivity, and uniform dimensional precision. It is the preferred protective sheath for demanding applications above 1400°C. The above installation, comparison, lifetime, and customization data provide practical guidance for selection and use.

For further information or to discuss your specific requirements, please contact us directly.

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