| 摘要 |
<p>Since a branch pipe (2) is joined via a cover plate (4) fixed to an outer peripheral surface (1A) of a main pipe (1), the manufacturing cost of the cover plate (4) can be suppressed compared to casting barrel-like ironware having a complicated shape, and since the cover plate (4) is fixed to the main pipe (1) using fillet welding, a machining cost can also be reduced. Moreover, since a protrusion surface portion (42) having a thin portion (44) with a plate thickness thinner than a connection surface portion (41) is formed in the cover plate (4), when transmitting stress from the branch pipe (2) connected to the connection surface portion (41) to the main pipe (1), the thin portion (44) is suitably deformed, which makes it possible to alleviate the stress concentration to the main pipe (1), and thus it is possible to improve fatigue resistance to fluctuating stress.</p> |
