Publications and presentations

The adoption of magnesium and magnesium alloys is an interesting option for lightening the car body in the automotive field. The weldability of magnesium is affected by the low melting temperature and the reduced range between melting and boiling temperature. In case of excessive heat input, the magnesium begins to boil, generating gas porosity and spattering. GMAW short arc welding fine tuned allows the heat input reduction, even if the poor wettability due to the high cooling speed at the weld start promotes lack of fusion and other imperfections. In this article the GMAW short arc optimized for magnesium alloys is described. More in detail, the focus is in the heat input control, with the target of establishing the process limits and proposing solutions for increasing the wettability, specially at the weld start, close to the fusion line.

Welding thin steel plates using laser beam technologies is an essential process in many manufacturing sectors, such as the home appliance sector, the vacuum technology sector or the medical equipment sector. A problem that the industry faces, is the deformation caused by residual stresses during laser welding. The standard methods to combat this, such as fixings and clamps, tend to be expensive and restrictive. The focus in the present study is on implementing a technique involving additional heat sources, which can reduce residual stresses in the plates and therefore optimize the outcome of the entire laser welding process. The experiment consists of two 1 mm Nickel-Chromium steel plates (1.4301) being laser welded to each other in a square butt weld. The special characteristics of the steel used, its high thermal expansion and low thermal conductivity, make it a good test subject for the problem at hand. The numerical simulation of the problem was used for a finer understanding of the processes and a better control of determining factors such as the temperature curves and the deformation of the steel plates.