Quantifying Carbide Banding Severity in Tool Steels for Cell Stamping Dies
Quantifying tool steel carbide banding via ASTM E1268 stereology prevents micro-chipping and premature fracture in high-takt battery cell stamping dies.
Micro-Galling
Meaning
Surface friction damage occurs at the microscopic level when two metallic surfaces slide against each other under high pressure. Stamping operations encounter micro-galling when small metallic particles transfer from the sheet metal to the punch surface. This transfer creates tiny raised bumps that score subsequent parts.
The defect degrades the surface quality of battery casings. It represents the early stage of tool wear that precedes larger adhesive failures.
Wear Mechanism
High-speed metal forming generates localized heat that softens the surface of the tooling steel. In the presence of micro-galling, these softened areas bond with the zinc or aluminum coating of the processed sheet. This adhesion grows with each stroke as more material accumulates on the die face.
Prevention Method
Tooling coatings like chromium nitride reduce the adhesion between the die and the workpiece. Corrective lubrication prevents the onset of micro-galling by maintaining a thin protective barrier between the sliding metal surfaces. This intervention is essential for high-speed automated production.
Production Impact
Quality inspections reject finished battery cans that feature surface scratches or uneven walls. The growth of micro-galling forces operators to halt the press line for polishing or die replacement. This maintenance reduces the overall equipment effectiveness of the manufacturing plant.