Comparison between continuous wave and pulsed Nd:YAG laser cladding of stellite 6

The comparison of melt pool temperature and the clad formation between continuous wave and pulsed Nd:YAG laser cladding of stellite 6 on stainless steel was made. The melt pool temperature in the CW laser cladding is roughly constant and increases with laser power, whereas the melt pool temperature in the pulsed laser cladding shows large fluctuation. Both pulse peak temperature ( Tp ) and the duration ( t1 ) when the melt pool temperature is above the melting point of stellite 6 powder increase with laser power. Clad height of the CW laser cladding increases smoothly with the laser power due to the increase of melt pool temperature (size), however, the increase of clad height of the pulsed laser cladding with the laser power is faster because of the increases of both Tp and t1 . For the same average power, the clad height in pulsed laser cladding at high pulse frequency is higher than that at the lower pulse frequency, and the total clad thickness in pulsed laser cladding is higher than that in CW laser cladding due to the effect of peak power. Therefore, higher powder mass flow rate is required for pulsed laser cladding.