| 摘要 |
PURPOSE:To enable to improve the sealing capability at the contacting part of a header plate with a tube by a method wherein a soft metal layer is interposed between the collared hole part of the header plate and the tube. CONSTITUTION:The metal layer 51, which is softer than the core material of the header plate 5 and the tube 1, is cladded onto the inside surface of the header plate 5. Because the tube 1 is expanded after being inserted in the collared hole part with said cladded metal layer 51 interposed between the core material of the header plate 5 and the tube 1, minute gaps between the hole part and the tube 1 are filled up by the deformation of the soft metal layer 51, the deformation of which is produced by expanding the tube and made in response to the outer surface roughness of the tube 1, resulting in certainly sealing even minute leakage and improving the sealing capability. |
