TUBULAR-MEMBER FLANGE COUPLING

摘要

The production process is shortened and the manufacturing costs are reduced. The present invention is a tubular-member flange coupling (8) in which a top or bottom end of a circumferential portion is mated to a bottom or top end of a tubular member (7) to couple the tubular members (7) to each other. A recess (16) having a substantially U-shape in cross-section is provided around a circumferential direction in a surface to be connected to the tubular member (7) at a position radially inward of a surface to be mated to the tubular member (7).