FLANGING METHOD, FLANGING SYSTEM, AND PRESSED MEMBER

The invention relates to a flanging method, a flanging system, and a pressed member. The present invention relates to a pressed member in which an upstanding portion is formed around a through-hole, and the objective of the present invention is to provide a technique relating to flanging with which it is possible to form a satisfactory flat portion at the periphery of the through-hole. This flanging method includes: a preliminary shaping step of causing a part 49 in which a through-hole 12 is to be formed to protrude outward with a tapered shape, at the periphery of which an inclined portion 50 is formed; a punching step of forming the through-hole 12; and a main shaping step of shaping the periphery of the through-hole 12 and part of the inclined portion 50, on the through-hole 12 side thereof, in the pressed member 10, into an upstanding portion 13, and shaping the remaining part of the inclined portion 50 into a non-metallic seal attaching surface 14 around the upstanding portion 13. In the preliminary sha