Real-time monitoring of laser hot-wire cladding of Inconel 625

• A comparison was made between laser hot-wire cladding and laser cold-wire cladding.
• The stability of the laser hot-wire cladding process was monitored by using a spectrometer.
• The plasma intensity and the calculated electron temperature were analyzed and discussed.
• The effects of applied voltage and laser power on the clad quality were investigated.

Laser hot-wire cladding (LHWC), characterized by resistance heating of the wire, largely increases the productivity and saves the laser energy. However, the main issue of applying this method is the occurrence of arcing which causes spatters and affects the stability of the process. In this study, an optical spectrometer was used for real-time monitoring of the LHWC process. The corresponding plasma intensity was analyzed under various operating conditions. The electron temperature of the plasma was calculated for elements of nickel and chromium that mainly comprised the plasma plume. There was a correlation between the electron temperature and the stability of the process. The characteristics of the resulted clad were also investigated by measuring the dilution, hardness and microstructure.