Meaning
Capacity of a coated metal surface to withstand material transfer and surface damage during sliding contact under high pressure. Evaluation of galling resistance nickel plated steel is required for deep drawing battery cans where the sheet metal slides over die radii. The nickel layer acts as a barrier to prevent the base steel from welding to the tool.
Proper coating prevents the surface from tearing and creating debris.
Surface Interaction
Molecular bonds form between the tool and the workpiece when the lubricant film fails. In the case of galling resistance nickel plated steel the hardness and smoothness of the plating determine how well the material flows. Harder coatings generally resist adhesive wear better than soft ones.
Testing Method
Standardized procedures like the twist compression test measure this property. Values for galling resistance nickel plated steel are expressed as the threshold pressure at which surface damage becomes visible. High values indicate the material can undergo aggressive forming without requiring excessive lubrication.
Coating Integrity
Ductility of the nickel layer must match the deformation of the steel substrate. If the plating is too brittle it will crack and allow the steel to contact the tool directly, which negates the galling resistance nickel plated steel benefits. Proper annealing of the plated strip ensures that the coating remains intact even at the corners of a 4680 cell.
This integrity maintains the corrosion protection throughout the life of the battery. Adhesion between the nickel and the steel must be perfect to prevent delamination under the intense shear forces of the ironing rings. Microscopic checks confirm that the interface is free of contamination.
