Vaporization of alloying elements during laser beam welding adversely affects weld metal composition and properties. Alloying element vaporization and weld metal composition change during partial and complete joint penetration keyhole mode Nd:YAG laser welding of two stainless steels containing different concentrations of manganese were examined experimentally and theoretically. The keyhole and weld pool geometry and the temperature field were computed from a well-tested, three-dimensional heat transfer and fluid flow model, and the results were used in a model for the calculation of weld metal composition change based on the principles of transport phenomena, kinetics, and thermodynamics. The results showed that vaporization from the keyhole was the most pronounced source of alloying element loss for all welding conditions. The weld metal composition was spatially homogeneous, but the concentration of manganese decreased while the concentration of iron slightly increased for all welding conditions. The change in the weld metal composition was much more pronounced for the higher manganese steel. The change in the weld metal composition was much more sensitive to laser power than welding speed for both partial and complete joint penetration welds.
|Published - Jul 2017
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys