1997 Volume 15 Issue 3 Pages 453-458
The formation of porosity in CO2 laser welding of brazed Al alloy plate was investigated. In order to evaluate the influence of brazing layer on the porosity formation, two types of specimens were welded. One was the brazed plate in which two plates were bonded, and the other was the Al plate without brazing layer. The obtained results are as follows.
(1) The number of porosity was less in the weld fusion zone of Al alloy plate than that of the brazed plate. It was made clear that melting the brazing layer caused the porosity formation.
(2) The joint shape, in which the brazing layer in weld groove was removed, was significant for reducing the porosity.
(3) High speed welding was effective for reducing the porosity in the brazed plate. It was suggested that high speed welding narrowed the melted zone of brazing layer, leading to the reduction in porosity.