TUBULAR BODY MANUFACTURING METHOD, AND POWDER-COATING FILM FORMING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a tubular body, in which a powder coating film formed on the inner peripheral surface is hardly cracked.SOLUTION: A shell 900 comprises: a socket 910 having an earthquake-resistant structure; and a straight section 920 continuing to the socket 910. The inner circumference 951 of the socket 910 is formed with a recess 993 for accommodating a lock ring 720. The recess 993 is formed with a socket powder coating film. The inner circumference 952 of the straight section 920 is formed at least partially with a straight section powder coating film. The hardness of the socket powder coating film is lower than that of the straight section powder coating film.SELECTED DRAWING: Figure 4