The effect of welding speed on mechanical and microstructural properties of 5754 Al (AlMg3) alloy joined by laser welding

5754 (AlMg3) alloys have advantages such as good strength, perfect corrosion resistance and cold forming in addition to the low specific density. Because of these advantages, they are commonly used in automotive, chemical and food industries, and especially in the vessel and yacht industry. However, in spite of having such important and common areas of usage, it is very difficult to join Al and its alloys by traditional welding methods. This study focused on joining of 5754 Al alloy materials, which are hard to be joined by the traditional welding methods but have common areas of usage, by using the laser welding method. Laser welding method has many advantages such as the low heat input, deep penetration, low residual stress, and distortion compared to traditional welding methods. For this purpose, 3 mm thick 5754 Al alloy sheets were joined by using the laser welding method. The welding processes was carried out selecting three welding speeds (3, 4.8, and 6 m min(-1)). The macrostructure, microstructure, hardness, tensile, and impact strength properties of the samples taken from the welded joints were examined. It was observed that micro-porosity and micro-void defects formed in the microstructure of the weld metal. The rate and size of these defects increased with increasing welding speed. The increase in the welding speed decreased the amount of the accumulated metal and the penetration rate. The mechanical properties were also negatively affected by the increase in the welding speed.