Views: 0 Author: Site Editor Publish Time: 2025-07-02 Origin: Site
In high-temperature industrial processes, such as ceramics manufacturing, powder metallurgy, and glass production, kiln furniture plays a vital role in supporting products during firing. Despite advances in kiln technology and temperature control, thermal shock resistance of kiln furniture remains a fundamental factor that determines product quality and yield. Frequent and rapid heating and cooling cycles cause significant stress on kiln furniture materials, and without proper resistance to these shocks, premature failure can occur, resulting in product loss, production delays, and increased operational costs.
At YUFENG, with over three decades of expertise in refractory materials and advanced ceramics, we understand the challenges posed by thermal shock and design kiln furniture to maximize durability and performance. This article explores the impact of thermal shock resistance on kiln furniture longevity and how it directly affects finished product yield.
Industrial kilns routinely expose their internal components to extreme temperature fluctuations. A single firing cycle can involve rapid heating to temperatures exceeding 1400°C, followed by cooling down to ambient conditions. This cyclical thermal loading causes materials inside the kiln to undergo expansion and contraction repeatedly.
Thermal shock occurs when the temperature changes so quickly that the material cannot uniformly expand or contract. This leads to internal stresses that may exceed the material’s strength, causing cracks or fractures. Kiln furniture, such as shelves, setters, plates, and supports, is particularly vulnerable because it must carry heavy loads while maintaining dimensional stability under these thermal stresses.
Moreover, temperature gradients can form across kiln furniture surfaces. For example, the side facing the heat source might expand faster than the shaded side, increasing the likelihood of stress concentration and failure. Since kiln furniture directly supports fired goods, any deformation or damage to these supports can negatively impact product shape, surface quality, or cause breakage.
When kiln furniture suffers thermal shock, initial damage usually begins at the microscopic level. Tiny cracks—called microcracks—develop inside the ceramic or refractory structure. Although not immediately visible, these microcracks weaken the material internally and grow larger with each firing cycle.
As the damage progresses, spalling may occur. Spalling is the detachment of small flakes or layers from the surface, which can fall onto the products below and cause surface blemishes or glaze defects. In extreme cases, catastrophic breakage may happen, where a shelf or support collapses suddenly.
Such failures disrupt production. A broken shelf can crush products in the kiln, leading to batch rejection. Cleanup and repairs result in kiln downtime, lowering throughput and increasing operational costs. Furthermore, broken pieces inside the kiln may damage the kiln’s refractory lining or other equipment, adding to repair expenses.
Thermal shock-induced failures are thus a significant cause of yield loss and unexpected maintenance in firing operations.
To resist thermal shock, kiln furniture materials must combine low thermal expansion with high mechanical strength and fracture toughness at elevated temperatures.
Low thermal expansion reduces the magnitude of dimensional changes during heating and cooling, thereby minimizing internal stress.
High mechanical strength ensures the material can withstand the stresses generated.
Fracture toughness helps prevent crack propagation.
Common kiln furniture materials with good thermal shock resistance include:
Cordierite-mullite composites: Cordierite offers one of the lowest thermal expansion coefficients among ceramics, while mullite adds mechanical strength and chemical stability. This combination is widely used for ceramic kiln shelves and setters.
Silicon carbide (SiC): SiC has excellent thermal conductivity, allowing rapid temperature equalization and reducing thermal gradients. It also has high mechanical strength and is ideal for high-speed and metallurgical kilns.
Alumina-based ceramics: High-purity alumina offers excellent mechanical strength and chemical resistance but generally has higher thermal expansion than cordierite.
At YUFENG, we carefully select and engineer materials based on your firing temperature, atmosphere, and product weight. Our kiln furniture products meet strict ISO9001 quality management standards, ensuring consistent thermal shock resistance tailored to industrial requirements.
Material choice alone is not enough. The structural design of kiln furniture plays a crucial role in mitigating thermal shock effects.
Slotted or segmented plates: Introducing controlled gaps or slots allows parts to expand freely without building up stress.
Reinforced ribs and lightweight cross-sections: Ribs increase stiffness and reduce deformation without adding excessive mass, which would otherwise increase thermal inertia.
Curved or rounded edges: Sharp corners concentrate stress and are more prone to cracking; smoother profiles improve durability.
Airflow-optimized geometry: Designs that promote uniform airflow help maintain even temperatures, minimizing gradients that cause thermal stress.
In addition, surface treatments and coatings can improve resistance to surface degradation and spalling.
YUFENG works with customers to customize kiln furniture designs, using advanced modeling techniques to predict stress distribution and optimize performance in specific kiln setups.
While robust materials and design reduce failure risks, all kiln furniture eventually degrades. A proactive maintenance strategy is essential to maximize life and prevent unexpected shutdowns.
Visual inspections detect early signs of cracking or distortion.
Thermal imaging during operation highlights uneven heating or cooling, revealing areas under stress.
Scheduled replacement based on usage cycles ensures timely renewal before failures occur.
Digital monitoring and IoT integration in modern kilns allow real-time tracking of temperature and structural health, enabling predictive analytics.
Implementing predictive maintenance helps plan downtime, reduce emergency repairs, and sustain consistent production quality.
YUFENG supports customers with technical guidance on maintenance best practices, helping to balance cost and reliability.
Thermal shock resistance in kiln furniture is a critical, though often overlooked, factor that directly impacts the yield and quality of fired products. Frequent and rapid temperature changes impose severe stresses that can cause microcracking, spalling, and structural failure, leading to product loss and costly downtime. By selecting materials with low thermal expansion and high mechanical strength, such as cordierite-mullite composites or silicon carbide, and combining these with intelligent structural design to minimize stress concentrations, manufacturers can significantly improve kiln furniture durability. Furthermore, incorporating predictive maintenance strategies helps detect and address potential failures before they disrupt production. At YUFENG, we leverage decades of expertise in advanced ceramics and refractory materials to provide kiln furniture solutions that meet the highest standards of thermal shock resistance and performance. Investing in high-quality kiln furniture from trusted manufacturers like YUFENG is essential for sustaining product yield, maintaining process consistency, and ultimately achieving long-term operational success. Contact us today to discover how our specialized kiln furniture can enhance your kiln’s reliability and efficiency.
