How are Aluminum Castings repaired?
Aluminum Alloy castings scrapped in the foundry because of surface defects and lack of dimensional integrity can be salvaged by welding except if they present massive porosity. Gas tungsten arc welding (GTAW) with high frequency stabilized Alternating Current is normally used to repair sound castings. Inclusions should be prevented by taking care to avoid touching the surface with the pure tungsten electrode. Argon with or without helium can be used as a shield. Helium helps generating a hotter arc if necessary. To prepare for welding one should remove defects, especially cracks, by dry chipping with a rounded tool or by hand milling, to obtain a smooth area. One should never attempt to weld on the original casting external rough surface without first removing the oxidized layer. Removal of oil and grease is performed using vapor degreasing or clean solvents.Use of acid etch is not recommended. If impregnation was applied, it should be removed before welding. A clean stainless steel wi
