Patent ID: 7575782

Claim:
A method for depositing an oil agent on a workpiece, comprising: a removal step of immersing a workpiece having a remaining oil agent in a degreasing solution, taking the workpiece out of the degreasing solution and cleaning the workpiece by water washing so as to remove all the oil agent deposited on the workpiece; an oil agent deposition step of immersing the workpiece wet with water after the water washing in an oil agent solution containing a water-soluble oil agent dissolved in water, taking the workpiece out of the oil agent solution and drying the workpiece so as to deposit a predetermined amount of the water-soluble oil agent on the workpiece; and a caulking step of caulking the workpiece having deposited thereon a predetermined amount of the water-soluble oil agent and a step of heating the caulked workpiece to a temperature of 400° C. or higher to thereby decompose and gasify the water-soluble oil agent that had been deposited on the workpiece.