In high-temperature kiln operations, silicon carbide (SiC) rollers are widely used for their strength and thermal stability.
However, under continuous load and elevated temperature, some rollers exhibit gradual bending—known as creep deformation.

This case study explains why creep occurs and how material and design optimization can significantly improve long-term stability.

Typical working conditions include:

• Temperature: 800–1200°C+
• Load: Continuous (self-weight + product load)
• Operation mode: Long-duration or continuous production

Under these conditions, even high-performance ceramics can experience time-dependent deformation.

A customer reported the following issues:

• Gradual sagging at the center of rollers
• No obvious corrosion, but increasing deformation over time
• Significant bending after 3–6 months of operation

This resulted in:

• Unstable material transport
• Uneven heating
• Increased defect rate
• Frequent replacement

Creep is a time-dependent deformation that occurs when a material is exposed to:

High temperature + constant stress

At elevated temperatures:

• Atomic mobility increases
• Material stiffness decreases
• Resistance to deformation is reduced

Even moderate loads can cause deformation over time.

Rollers are constantly subjected to:

• Self-weight
• Product load

This leads to:

Gradual accumulation of strain over time

At the microscopic level:

• Grain boundary sliding occurs
• Pores grow and coalesce
• Local structure becomes less rigid

Resulting in reduced mechanical stability

Higher porosity → easier deformation

Higher modulus → better resistance to bending

Higher temperature → faster creep rate

Longer span → higher bending stress

To address creep deformation, the following improvements were implemented:

Use of high-density SiC (SSiC):

• Density ≥ 3.05 g/cm³
• Open porosity ≤ 0.2%
• High elastic modulus (~420–430 GPa)

Significantly improves creep resistance

• Reduced span length
• Improved support distribution

Lower bending stress at the center

• Controlled high-temperature exposure
• Avoided local overheating

After optimization:

• No visible deformation after 12+ months
• Stable roller alignment
• Reduced replacement frequency
• Improved production consistency

Creep is not a sudden failure—it is a progressive structural issue

In high-temperature applications, the key property is not just strength, but:

Creep resistance

For high-temperature kiln applications:

• Material density and microstructure are critical
• Design and span control matter
• Long-term stability depends on creep resistance

Optimized SiC solutions can significantly extend service life and reduce downtime