摘要 |
In a heat exchanger plate freedom of design of the flow channel is improved. A flat main body on a surface of which is formed at least one first groove having a rectangular cross-sectional shape, and a second groove having a rectangular cross-sectional shape that is narrower than the first groove, and that is formed following along opposite side faces of the first groove at a center of a bottom face of the first groove; and a flat cover which covers an entire surface of the main body, and on a rear face of which is formed a protrusion whose top face contacts a bottom face of the first groove and whose opposite side faces contact opposite side faces of the first groove, when the cover is superposed on the surface of the main body, and which forms a flow channel by means of a top face thereof and the second groove, are joined by friction stir welding.
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