Studies on the Porosity in Welding Joints (Roport 1)

Relation between Welding Procedure and Results of Gas Analysis in Aluminium Alloy

Abstract

Recently, in order to satisfy the increasing demands in atomic power industry, aluminium alloys are used in many parts of the reactor, e.g., the canning material of the fuel element, deuteriem vessel, reactor vessel, pipe-lines and so on.
In thsoe cases high quality is required of their welding performance, porosity being one of the most important defects among those found in welded joints.
Porosity in welds not only decreases the mechanical properties and corrosion resistance of welded joints, but seems to cause the activation of gases included in welds under the irradiation.
The experimental resuts are as follows :
1) As the time after cleaning passed, the gas contents increased remarkably.
2) As heat input increased, the gas contents decreased in all plate thicknesses (6, 12 and 20mm).
3) The gas contents of preheated welds were than those of untreated welds.
Above results agreed with the results of the X-ray measurement of porosity.