Friction behavior evaluation of an EBT zinc-coated trip 700 steel sheet through flat friction tests

HSLA steels are commonly used as stamped parts for cars with protection coatings. These coatings must have properties that are suitable for the friction phenomenon, which appears in stamping processes, and a good adhesion to steel. Structured coating surfaces have been developed to offer special behavior to lubrication. In such cases, the friction conditions, like pressure and velocity, may strongly influence the friction behavior. In this work, a TRIP 700 EBT zinc-coated steel is researched under different conditions by flat face friction. Different oil coating thicknesses have also been evaluated. The results indicate that pressure significantly influences the coefficient of friction, which is justified through micro-hydrodynamic effects. The micro-hydrodynamic regime is a result of the plastic deformation of zinc, which creates high hydrostatic pressure on the entrapped lubricant. 3D Abbott curves are used to analyze the changes on the surface with pressure for low velocity values. Finally, balanced wear and plowing are justified for these conditions.