Roll Face Corrosion in Roll Forming Machines – Causes, Inspection, Troubleshooting & Repair Guide
Roll Face Corrosion
Roll Forming Machine Tooling & Pass Design Failure Guide
Roll face corrosion is a tooling degradation problem in roll forming machines where the working surface of the roll tooling develops corrosion due to exposure to moisture, chemicals, or environmental contaminants. The roll face is the active forming surface that comes into direct contact with the metal strip during the roll forming process.
Because the roll face must maintain a smooth and precisely machined profile, corrosion on this surface can significantly affect the forming process and the quality of the finished product.
Roll forming tooling is typically manufactured from hardened alloy steel and may be coated with protective layers such as chrome plating. These protective surfaces are designed to resist wear and corrosion during continuous production.
However, when roll faces are exposed to moisture or corrosive environments without adequate protection, oxidation may occur. This oxidation can gradually develop into corrosion, which may cause surface roughness, pitting, or material loss on the roll face.
Corrosion damage is particularly problematic in roll forming operations producing painted or coated materials where surface quality is critical.
Roll face corrosion commonly affects roll forming machines producing:
- metal roofing panels
- standing seam roofing systems
- architectural metal panels
- metal wall cladding panels
- structural roof deck profiles
- steel framing components
Typical production symptoms associated with roll face corrosion include:
- rust spots on roll surfaces
- rough or uneven roll contact areas
- scratches or marks on finished panels
- increased friction during forming
- gradual deterioration of product surface quality
If corrosion progresses further, the roll surface may develop pits or material loss that alters the geometry of the roll tooling. This can lead to profile inaccuracies and accelerated tooling wear.
Maintaining clean and protected roll surfaces is essential for preserving tooling life and maintaining consistent roll forming production.
Causes of Wear or Failure
Roll face corrosion typically occurs when the roll surface is exposed to environmental conditions that promote oxidation and chemical reactions with the steel surface.
Several factors may contribute to this problem.
Moisture Exposure
Humidity and water exposure are among the most common causes of corrosion on roll faces.
Moisture may accumulate due to:
- humid factory environments
- condensation during temperature changes
- water leaks near the machine
Improper Tool Storage
Roll tooling stored without protective coatings or coverings may develop corrosion over time.
Long periods of storage increase the likelihood of rust formation.
Damaged Protective Coatings
Rolls often rely on protective coatings such as chrome plating to prevent corrosion.
If the coating becomes damaged or worn, the underlying steel surface may become exposed.
Chemical Contamination
Exposure to industrial chemicals, acidic vapors, or cleaning agents may accelerate corrosion on roll surfaces.
Wet Coil Material
Incoming metal coils that contain moisture or condensation may transfer water to the roll surfaces during forming.
Idle Machine Conditions
Machines that remain idle for extended periods without protective measures may develop corrosion on roll faces.
Why It Happened and What Caused It
From a materials engineering perspective, roll face corrosion occurs when the steel surface reacts chemically with oxygen and moisture in the surrounding environment.
This reaction forms iron oxide, commonly known as rust.
When the corrosion process begins, a thin oxide layer forms on the metal surface. If the conditions remain favorable for corrosion, this layer can grow thicker and may eventually cause surface damage.
On roll forming tooling, corrosion often begins as small rust spots or discoloration on the roll face.
Over time, the corrosion may spread across the surface and create rough areas that interfere with the smooth contact between the roll and the strip.
These rough areas may cause scratching or marking of the strip as it passes through the forming station.
If corrosion continues to progress, it may cause pitting or localized material loss on the roll face.
Because roll forming tooling must maintain precise shapes and smooth surfaces, even small corrosion pits can disrupt the forming process.
Maintaining protective coatings and controlling environmental conditions helps prevent corrosion damage.
How to Inspect the Problem
Inspection Procedure
Diagnosing roll face corrosion requires careful inspection of the roll tooling and the finished panels.
Step 1 – Inspect Roll Faces
Examine the working surfaces of the rolls for signs of rust, discoloration, or surface roughness.
Step 2 – Inspect Finished Panels
Look for scratches, marks, or contamination on panel surfaces that may correspond to corroded roll areas.
Step 3 – Inspect Protective Coatings
Check whether chrome plating or other protective coatings remain intact on the roll faces.
Step 4 – Inspect Tool Storage Conditions
Evaluate whether roll tooling is being stored in dry and protected environments.
Step 5 – Check Environmental Conditions
Monitor humidity levels and potential sources of moisture near the roll forming machine.
Step-by-Step Technician Guide – How to Fix
Repairing roll face corrosion requires restoring the smooth surface of the roll tooling.
Method 1 – Clean Surface Rust
Light corrosion may be removed using fine polishing or non-abrasive cleaning methods.
Method 2 – Polish the Roll Face
Polishing may restore the smooth finish required for forming.
Method 3 – Regrind the Roll Tooling
If corrosion has caused pitting or deeper surface damage, precision grinding may be necessary.
Method 4 – Reapply Protective Coatings
Chrome plating or protective coatings may be applied to prevent future corrosion.
Method 5 – Improve Environmental Controls
Reducing humidity and protecting tooling during downtime helps prevent further corrosion.
Preventative Maintenance Tips
Preventing roll face corrosion requires proper tooling care and environmental control.
Apply Protective Oil Films
Light oil coatings can protect roll surfaces during storage.
Maintain Low Humidity in Production Areas
Controlling humidity helps prevent oxidation and corrosion.
Cover Tooling During Downtime
Protective covers prevent exposure to moisture and contaminants.
Inspect Rolls Before Production
Routine inspection helps detect corrosion early.
Store Tooling Properly
Keep roll tooling in dry environments when not in use.
FAQ Section
What causes corrosion on roll forming rolls?
Moisture exposure, chemical contamination, and damaged protective coatings may cause corrosion.
Can roll face corrosion affect panel quality?
Yes. Corroded roll surfaces may scratch or mark finished panels.
How can corrosion be removed from roll faces?
Light corrosion may be removed through cleaning and polishing.
When should corroded rolls be replaced?
If corrosion causes significant pitting or geometry damage, replacement may be required.
Can chrome plating prevent corrosion?
Yes. Chrome plating helps protect the roll surface from oxidation.
How can roll face corrosion be prevented?
Proper storage, protective coatings, and humidity control help prevent corrosion.