| 摘要 |
<p>A fin insert (80) shapes the edges of an enhanced metallic strip (72, 74, 76) prior to shaping the strip into a tube and welding. The edges of the metallic strip are shaped so that the longitudinal edges of the unenhanced portion (76) of the strip contact during welding thereby reducing fluctuations in metal volume at the weld site that cause weld instability.</p> |
