•The thermal-mechanical simulation of the coating was carried out in order to investigate the residual stresses and strains.•The most important factors for the formation of crack in the coating layer ...are the geometrical shape of the cladding.•When the wetting angle of the coating is less than 44º, the stress concentration is maximized at the top of the coating.•When the wetting angle is more than 44º, the stress concentration the crack formation is transferred to the substrate.
In the present research, thermal–mechanical simulation of laser cladding of Stellite 6 powder on X19CrMoNbVN11-1 steel substrate was carried out to study the influence of scanning speed and laser power on the remaining stresses/strains and thus the formation of cracks in the cladding layer. In order to demonstrate the accuracy of the simulation results in prediction of the crack formation, the laser cladding process was also implemented experimentally. The results have shown that the highest temperature of the molten pool (1753 °C) was obtained at a laser power of 250 W, a powder injection rate of 0.3 g/s and a scanning speed of 3 mm/s. With the increase in scanning speed, the geometric shape of the cladding layer has changed from a semicircle to an oval shape. Moreover, at low scanning speed, the maximum strain is produced in the substrate and at high scanning speed, the maximum strain is created at the top of the coating layer. The lowest value of residual stress and strain was obtained at a scanning speed of 3 mm/s, while at a scanning speed of 5 mm/s the highest value of residual stress and strain was obtained. Furthermore, when the wetting angle is greater than 44°, the stress concentration is transferred from the top of the cladding layer to the substrate and the possibility of crack formation decreases.
This investigation aims to study the effect of laser cladding parameters on the microstructure of Stellite 6 on the X19CrMoNbVN11-1 stainless-steel substrate. First, Stellite 6 powder was coated on ...the X19CrMoNbVN11-1 substrate using the laser cladding method. The effect of laser cladding parameters (i.e., laser power, scanning speed, and powder feed rate) was studied on the microstructure of deposits. The secondary dendritic arm spacing was assessed, and the structural defects were studied (e.g., lack of bonding, porosity, and crack). The results revealed that the microstructure has changed from coating/substrate interface to coating surface, from plate-cellular to columnar and equiaxed dendrites. Also, an increase in the laser power increased the cellular structure in the coating/substrate interface and equiaxed dendrites in the coating surface. The cooling rate (G × R) increased by increasing the scanning and powder injection rates. The microstructure of the Stellite 6 was composed of cobalt solid-solution γFCC.
