Thermal shock resistance is one of the most vital properties in the design and application of refractory materials. Sudden temperature changes can severely damage refractory linings if not properly accounted for.
What Is Thermal Shock?
Thermal shock occurs when materials are rapidly exposed to temperature variations, leading to expansion or contraction that causes cracking or spalling. The resistance to this is essential for materials in furnaces, kilns, and reactors.
Materials with High Resistance
- Silica bricks: Excellent for steady temperatures but sensitive to shock.
- Mullite and alumina: Offer balanced mechanical strength and thermal shock resistance.
- Fused cast AZS: Used in glass furnaces where both corrosion and shock are factors.
Improving Shock Resistance
Strategies include using materials with lower thermal expansion coefficients, adding fibers or microcracks to absorb stress, and controlling heat-up and cool-down cycles during operation.
Application by Sector
- Glass industry: Needs materials like AZS with superior shock resistance.
- Steel: Slag lines and ladles must withstand repeated thermal cycling.
- Cement: Preheater linings are exposed to frequent and abrupt thermal changes.
Conclusion
Enhancing thermal shock resistance extends the lifespan of refractories and prevents costly breakdowns. A tailored approach based on sector and process is essential, and MXS Refractories helps clients assess and optimize their refractory choices accordingly.