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Controlling the quality of coatings is a significant objective. The large area parts require the construction of multi-track laser cladding layers, which are influenced by the overlapping conditions. This investigation deals with laser cladding technology, multi-track beads of 42C martensitic stainless steel were coated on FGS600-3A ductile cast iron with different overlap ratios. The percent overlap varied from 20% - 35% - 50% - 65% - 80%, which corresponds to 2.4 mm - 1.95 mm - 1.5 mm - 1.05 mm - 0.6 mm for multi-bead production. The optimum welding parameters were kept constant for production of specimens: laser power 1.3 kW and feed speed 8 mm/s, 3 layers of production were carried out. An experimental approach to investigate the porosity rate, crack and microhardness with variable overlap conditions is presented in this paper. In addition, digital image processing method was also used to calculate the porosity rate in the transverse and longitudinal surface. Vickers method was also employed to measure the hardness from base metal to surface of the coatings. It was found that by reducing the overlap distance, it is possible to drastically reduce the pore formation. The best compromise in terms of porosity was obtained in overlap distance 1.05 mm which corresponds to 65% overlap ratio. The highest microhardness values in the coating layer were obtained as 559.7 HV in specimen with 1.05 overlap distance. Experimental results on overlapped cladding layers of stainless steel on ductile cast iron show that it is useful for upcoming repair implementation of large parts suitable in the automotive sector.
Keywords: Laser cladding, overlap ratio, porosity, microhardness© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.