10 tips: Resist headbox corrosion in maintenance & operation

Corrosion can be minimized by adhering to the following maintenance and operating procedures:

1. Control pH - acidic conditions accelerate corrosion.
2. Clean or boil out interior surfaces as needed to remove contaminants.
3. Do not clean interior surfaces with abrasive cleaners, which cause fine scratches that can hang up fiber and initiate corrosion.
4. So not walk on polished stainless steel surfaces with contaminated or dirty shoes.
5. Cover all mild steel hose connections when entering a headbox for high pressure cleaning. Mild steel rubbed on stainless steel can result in corrosion. Metal tools should never contact stainless steel.
6. Clean knuckle bar area of slice body during wire changes and shutdowns. Fiber buildup and moisture an cause crevice corrosion on knuckle bar and brass clamps.
7. Keep apron and slice lips clean. Fiber buildup can cause pitting corrosion, affecting jet and delivery.
8. On older headboxes, paint mild steel - but not stainless steel.
9. To retard corrosion, periodically passivate, restoring the chrome oxide film on stainless steel surfaces. Before passivating, stainless steel should be cleaned with soap and hot water.
10. If damage to the polished surface occurs, contact the manufacturer to repair and repolish. Stainless steel can be tested to determine if contamination has occurred. Also, tests can be done to determine types of stainless steel.

For more information on headbox maintenance, contact your Valmet representative.