LUBRICANTS WITHOUT GRAPHITE FOR THE DROP-FORGING OF STEEL

In die forging, lubrication of dies is almost exclusively carried out by sprayable aqueous graphite suspensions. In this paper the demands on die lubricants are presented. Of major importance are the temperatures which occur in the active joint between the workpiece and die. In existing temperature conditions graphite-containing lubricants maintained their high-quality lubricating action by incorporated foreign gases. Among their disadvantages, their corrosive behaviour to dies, control equipment and machines and their high degree of environmental pollution have to be considered. The development of a graphite-free lubricant which eliminates the disadvantages mentioned and results in a prolonged service life of the die is reported. This new lubricant is based on calcium salts of fatty acids and has been successfully tested.