T.O. 33B-1-1Figure 6-45.Radiographic Examples of Welds (Sheet 2 of 2)6.8.17.17AluminumandMagnesiumWelds.Radiographic technique and equipment for examining welds in aluminum and magnesium alloys are nodifferent than methods used for steel welds. The discontinuities produced by fusion welding of aluminum andrevealed on film by radiography include:a.Entrapped gas, ranging from fine gas porosity to large gas holes. The porosity may be in line or atrandom.b.Inclusions of tungsten particles, foreign materials, f lux and oxide. Since the density of oxide films isnearly the same as that of aluminum, they will not produce a detailed indication on a radiographunless present in large quantities.c.Inadequate penetration.d.Incomplete fusion.e.Cracks.f.Surface irregularities.6.8.18SpotWelds.A special exposure technique is necessary for the inspection of spot welds. The welded areas are X-rayed witha low-voltage, high-intensity, beryllium-window X-ray tube on extremely fine grained films. Spot welds andseam welds produce X-ray images of aluminum and its alloys that are entirely different from those of anyother welding technique. Because of the rather large percentage of radiographically dense alloying constitu-ents that produce informative patterns, some of the high strength aluminum alloys are well suited for spotweld radiography. The images show positive indications of the following:a.Variations in weld nugget shape (oversize, undersize, absence, misshapen, doughnut and crescentshaped).b.Extrusion and expulsion of metal from nugget.c.Cracks.d.Foreign materials (for example, tip pickup).e.Porosity.f.Segregation of the alloying elements.g.Electrode impressions.Change 36-105
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