Welding technologies for aluminum alloy naval parts - propeller shaft guide bushing made of ALMG5

The article presents the welding technology of a "Guide bushing - propeller shaft" type made of AlMg5 material and the problems that arise during welding depending on the way of obtaining the product (cast or rolled) and the chemical composition. The components have thicknesses between 20 – 40 mm and their welding raises some problems related to the welding temperature and its maintenance during welding. Defects that appeared during welding, pores, cracks, breaks and others are presented. These defects occurred not due to the parameters of the welding regime but due to the way the casting was performed (gravitational and low temperature) and the presence of copper in the alloy. After checking the chemical composition, an attempt was made to remove the pores from the surface and near the surface, but without obtaining a corresponding result. The solution to this problem was to change the semi-finished product as a type of production. In conclusion, parts made by welding from cast aluminum alloys must first be carefully checked for non-destructiveness, microcracks and granulation (especially the degree of porosity) so that these factors do not become crack primers.