Causes Of Abnormal Deformation Of Sintering Furnace Mesh Belts

Stainless steel conveyor mesh belts for sintering furnaces naturally elongate under normal and high temperature conditions due to material properties; such inherent stretching is not regarded as abnormal deformation. This article analyzes non routine deformation including twisting, warping and side bending, which is mainly triggered by material, temperature, mechanical stress, furnace atmosphere and maintenance issues.

1. Improper Material Selection

2. Temperature Related Factors

• Over temperature operation: Long term service exceeds material temperature limits, e.g. 304 above 870 °C, 314 above 1150 °C. Accelerated atomic diffusion and grain boundary sliding lead to irreversible creep deformation. This failure mode is relatively rare in actual production.
• Uneven furnace temperature: Poorly arranged heating elements or inconsistent insulation create alternating hot cold zones. Differential thermal expansion generates internal stress beyond yield strength and causes local bending or twisting, frequently seen in gas fired furnaces.

3. Mechanical & Physical Factors

4. Furnace Atmosphere Effects

Carburization & nitriding: Under nitrogen based atmosphere, nitrides form from nitrogen reaction while hydrocarbon from lubricant burnout causes carburization. Chromium carbides / nitrides precipitate at grain boundaries, embrittling the material and reducing effective cross section. Severe cambering or fracture of spirals and cross rods may occur.

Oxidation reduction cycles: Protective chromium oxide film is destroyed in high temperature reducing atmosphere and regenerated in cooling zones. Repeated cycles accelerate material degradation.

Chemical reaction with workpieces: Metals such as copper form alloys with mesh belts at high temperature; corrosive gas leads to local hardening and embrittlement.

5. Design, Installation & Maintenance

Incorrect belt type selection (common models: K2, F2, RRW, F2W, K2W, A4), non standard commissioning without SOP, and lack of routine cleaning & inspection will shorten service life.

• Material selection: 310S (<1000 °C), 314 (<1150 °C) or Inconel for higher temperature.
• Control operating temperature and improve furnace temperature uniformity.
• Standardize installation with moderate and balanced tension.
• Distribute workpiece load evenly across belt width.
• Carry out regular cleaning, roller inspection and belt condition monitoring.