Ring molded article manufacturing method and ring material

1. A ring material configured for being subjected to forging to produce a ring molded article having two convex portions which respectively protrude on opposite sides of the ring molded article in a direction of a center axis thereof and extend in a direction of a circumference of the ring molded article, wherein the ring material comprises:

first and second side regions, wherein a straight line passing through centers of gravity of the first and second side regions is inclined by an angle relative to a center axis of the ring material, the first and second side regions are obtained by virtually dividing a one half section of the ring material which is configured for being placed inside two molds, based on a middle of a maximum height of the ring material in the direction of the center axis of the ring material, the angle of the straight line relative to the center axis of the ring material is 7 degrees to 40 degrees,

wherein a radially outer peripheral surface of the ring material relative to the center axis is formed in a substantially arcuate shape which protrudes radially outwardly in a cross section of the ring material along a plane parallel to the center axis and the straight line, and a radially inner peripheral surface of the ring material relative to the center axis is formed in a substantially arcuate shape which protrudes radially inwardly in a cross section of the ring material along the plane parallel to the center axis and the straight line.