LUBRICANT COMPOSITION FOR PLASTIC WORKING OF METAL AND METHOD FOR PLASTIC WORKING

摘要

PROBLEM TO BE SOLVED: To carry out a cold plastic working (e.g. drawing) of metal by using a lubricant which forms a lubricating film having high adhesiveness to the surface of a metal, decreases a friction and actualizes extension of tool life and improvement in product qualities and is removable by washing with water. SOLUTION: A water-soluble resin which comprises a high-molecular weight polyether polyester obtained by reacting a polyalkylene oxide with a tetrafunctional carboxylic acid or its salt or anhydride (e.g. pyromellitic acid dianhydride) and has 17-23 meq/g ether bond and 0.03-2 meq/g dissociation group (carboxylic acid group) is used as a lubricating film-forming component, preferably as a composition of the water-soluble resin mixed with fine particles. Water is added to the composition, the water-soluble resin is dissolved and applied to a metal. Otherwise, the composition is not diluted with water, applied to a metal at the melting point of the water-soluble resin or above and a plastic working is performed. The plastic working may be carried out while the applied resin is in a solution or in a molten state (before film formation) or may be performed after the resin is solidified and a film is formed.