Abstract: Provided is a mandrel which is inserted into a pipe material when the pipe material is bent, the mandrel including: a core member having a rod-shaped main body portion and a small-diameter portion which is provided on one end side of the main body portion and which is thinner than the main body portion; and a front end member which is provided on one end side of the core member and which is formed integrally with the core member so as to cover the small-diameter portion.

Abstract: Provided is a mandrel which is inserted into a pipe material when the pipe material is bent, the mandrel including: a core member having a rod-shaped main body portion and a small-diameter portion which is provided on one end side of the main body portion and which is thinner than the main body portion; and a front end member which is provided on one end side of the core member and which is formed integrally with the core member so as to cover the small-diameter portion.

Abstract: Provided is a method for producing, with good workability, a composite having a lightning-resistant layer that exhibits excellent adhesion to a resin-based composite and good fatigue properties. The method for producing a resin-based composite comprises a step of forming a laminate by successively laminating, on a first resin sheet (11) comprising mainly a fiber-reinforced resin, a conductive layer (12) formed from a resin containing a metal powder, and a second resin sheet (13) comprising mainly a fiber-reinforced resin, and a step of forming a resin-based composite (10) by baking the laminate to bond the first resin sheet (11), the conductive layer (12) and the second resin sheet (13).