Method for manufacturing metal auto parts and metal auto parts

摘要

It is an object of the present invention to provide a method for uniformly forming a film on an outer circumferential portion of a metal automotive part by preventing penetration of a coating substance into a portion thereof unnecessary to be coated with paint. The method for producing a columnar or cylindrical metal automotive part whose outer circumferential surface includes a portion to be coated with paint and a portion to be uncoated therewith includes the following processes: (1) a process of providing a convergent nozzle-shaped covering jig which covers an outer circumferential surface of the columnar or cylindrical part at an axial end thereof and covers the portion to be uncoated with the paint, with a gap formed between the covering jig and the outer circumferential surface of the part; (2) a process of discharging a gas from the gap toward an end of a nozzle of the covering jig with the columnar or cylindrical part being rotated; (3) a process of sticking a film-forming substance to the columnar or cylindrical part from an axial side surface thereof.