Method for producing porosity-free joints in laser beam welding of maraging steel 250

Laser beam welding of 4.5-mm-thick sheets of maraging steel 250 using a 4-kW ytterbium fiber laser was studied. Maraging steel 250 is widely used in the aerospace industry in applications that require high strength. Therefore, in order to join two parts made of maraging steel 250, it is essential to produce a high-quality weld that meets weld bead geometry requirements, without any porosity formation in the weld that may lead to premature fatigue failure. In order to achieve a reliable and repeatable welding process, we investigated the influence of welding parameters on the welded process responses, i.e., weld penetration depth, bead width, and potential formation of porosity. A complete model was developed using multiple regression analysis. Based on this model, we developed a method for selecting welding parameters that assure production of porosity-free welds with the required geometry. We used this method to automate the industrial welding process of a part-family of maraging steel 250 cylinders.