The Real Enemy of refractory materials is not high temperatures,but sudden Temperature Change (Thermal Shock)
2026/07/04
High heat alone is not the biggest problem for refractories. Rapid heating or cooling -- known as thermal shock--causes internal stress, cracking, and spalling. Even materials that handle 1600°C can fail quickly under sudden temperature changes.
Example: Electric arc furnace roof
- Cold scrap metal is charged into the furnace, touching the hot roof.
- Ordinary high-alumina bricks crack after just a few cycles.
Solution: Use magnesia-chrome bricks or magnesia-spinel bricks, which have better thermal shock resistance. Another approach: low-expansion materials like fused silica or silicon nitride-bonded silicon carbide.
Everyday analogy: A glass cup shatters when you pour boiling water into it – same principle.
