Laser induced heating of coated carbon steel sheets: Consideration of melting and Marangoni flow

Laser induced melting of coated carbon steel workpiece is simulated. The coating materials include tungsten carbide, alumina, and boron are incorporated in the simulations. The coating thickness is kept constant at 7.5 μm in the analysis. The enthalpy porosity method is used to account for the phase change in the irradiated region. The study is extended to include the influence of laser intensity transverse mode pattern (β) on the resulting melting characteristics. It is found that peak temperature predicted at the surface is higher for alumina and boron coatings than that of tungsten carbide coating. The influence of the laser intensity transverse mode pattern on the melting characteristics is considerable. Surface temperature predicted agrees with the thermocouple data.

► Marangoni flow developed in the melt pool is influenced by the material properties.
► Coating remains in solid phase for same coating materials while underlying steel undergoes a melting.
► Laser pulse intensity parameter has significant effect on the melt pool size and Marangoni flow.