Influence of cleaning pretreatments on tribological properties of zinc phosphated steels

Among lubrication processes for cold forging of steel, phosphating is the most common. Depending on contact between piece and phosphating solution, the success of this treatment depends on steel surface preparation. Despite this obvious fact, the influence of cleaning pretreatments such as degreasing and acid pickling are seldom considered from a mechanical point of view and specially from a tribological one. Through a tribological test, the preparation of the surface of steel billets to be zinc phosphated and soaped was studied. Having shown the importance of degreasing, this study tries to connect the parameters of warm acid pickling, such as bath composition and dipping time to the tribological performances of the coated part.