Effect of argon flow rate and standoff distance on the microstructure and wear behaviour of WC-CoCr TIG cladding

Abstract

This study examines the micro-hardness and abrasive wear resistance of WC-CoCr cladding produced by tungsten inert gas (TIG) welding process. The effect of argon flow rate and standoff distance on the microstructure and properties of the cladding was also investigated. The morphology of WC-CoCr powder and its corresponding claddings was examined by FE- SEM analysis. The tribological behaviour of cladding was analysed by using pin-on-disc wear tribometer. High hardness and wear resistance were observed at higher values of standoff distance and argon flow rate. Wear in the cladding is mainly due to pull out of tungsten carbide particles along with plastic flow caused by yielding and extrusion of CoCr binder.

Powder Plasma Transferred Arc Welding of Ni-Si-B+60 wt%WC and Ni-Cr-Si-B+45 wt%WC for Surface Cladding of Structural Steel

“…The lower presence of the WC particles resulting from higher dissolution of the WC particles at the subsurface was the reason for the deeper grooves caused by the quartz sand at higher PGFR values and the observation of a decline in the abrasive wear resistance at a PGFR of 1.5 L/min in Figure 17 a,b. These observations were consistent with other research works [ 37 , 38 ] that investigated the effects of gas flow rate on the mechanical and wear behavior of surface coatings using TIG and plasma spray approaches, respectively.…”

Synthetization of TiC surface hardening using TIG melting technique - The effect of working distance

“…Adding more voltage is one technique to instantly stabilize the arcing problem seeing this method potential to capture more preplaced powder and substrate to melt. Others had increased of hardness is associated with increased of working distance because of the melt that rapidly solidifies [7] As the gap is narrowed from 1.5 mm to 0.5 mm, fusion energy were high enough to cause extensive TiC and substrate melting followed by the enlargement of those HAZ. Under this condition the Gaussian energy distribution grows making increased of heat intensity which lead to the high melt depth and width of 1 mm and 3.47 mm respectively.…”

“…Increasing heat inputs, using special shielding gasses, or even adding fluxes to expand the melt volume may incur some amount of additional cost or complexity processing setup and techniques for experimental works. Very little information is available through publication to explain the beauty of manipulating working distances hence endeavoring bigger resolidified melt [7,8]. Altering working distances in favour to have less or more melt involved no additional cost.…”

The potential use of laser cladded functionally graded materials to mitigate degradation in boiler tube heat exchangers for power plant applications: A review

“…The laser energy density (LED) is measured in J/mm 2 and has a directly proportional relationship with laser power (P) as well as an inverse relationship to speed (V) and beam diameter (d), as shown in equation 2 [15]. Simply put, the energy dissipation rate as a function of time determines the molten pool size, which influences the solidification process, the morphology of the grain structure, and the geometrical characteristics of the FGM clads [143,144]. Further, an increase in scanning speed will reduce LED because the duration of laser metal interaction will be shortened since the laser beam cannot dwell longer during deposition, leading to a smaller melt pool.…”

“…This could be attributed to the melting force and flow viscous force of the Marangoni convention phenomenon that leads to suppression of the deposited layer upon melting. This leads to reduced clad height, while the melt pool volume expansion on the surface worsens the melted area, which in this case, increases the FGM clad width [143,144]. Therefore, it is without a doubt that the clad height must be smaller during the surface modification of boiler tubes to improve cost efficiency and reduce clad weight because it depends on the amount of FGM powders introduced to form layers during deposition.…”