Lubricant for metallic material working and a method of press working a metallic material

A method of press working a metallic material, by using a die assembly subjected to a surface treatment, after feeding a lubricant between the metallic material and the die assembly,

• the surface treatment being a treatment comprising a blasting of fine particles of high-speed tool steel having an average diameter of from 30 to 80 μm against the surface of the die assembly at a jet velocity of from 130 to 170 m/s, and then a blasting of fine particles of a ceramic material having an average diameter of from 40 to 70 μm against the surface of the die assembly at a jet velocity of from 130 to 170 m/s,
• wherein the lubricant comprises a mixture of a sulfur-based extreme pressure agent, an organic zinc compound, a calcium-based additive, and an ester compound, with a lubricant base oil, the lubricant being free from chlorine-based additives, wherein
• the sulfur-based extreme pressure agent comprises sulfurized fats or oil or a combination of sulfurized fats or oils and polysulfides and has a sulfur content of 5% to 8% by weight based on the total weight of the lubricant,
• the organic zinc compound comprises ZnDTP and comprises a zinc content of 0.5% to 1.3% by weight based on the total weight of the lubricant,
• the calcium-based additive comprises basic calcium sulfonate and has a calcium content of 0.5% to 1.5% by weight based on the total weight of the lubricant,
• the ester compound comprises at least one selected from the group consisting of polyol esters and complex esters and occupies a content of 1.0% by weight or higher based on the total weight of the lubricant, and
• the lubricant base oil comprises paraffinic mineral oils or naphthenic mineral oils.