PURPOSE: To reduce the generation of the breaking of a material such as the cutting of a can caused by galling in the process of working by providing the surface with a specified amt. of phosphate film.

CONSTITUTION: The surface of an aluminum alloy sheet for forming is provided with a phosphate film of 0.1 to 20g/m2. This is furthermore coated with animal and vegetable series lubricating oil or mineral series lubricating oil or synthetic lubricating oil or their mixed lubricating oil. As the aluminum alloy, e.g. 3004 alloy used for DI can barrels and 5052 and 5182 alloy utilized for can cover materials are used. In this way, the wear of a tool such as a die caused by coagulated materials is reduced, and the service life of the tool can be prolonged.