Journal of Welding Science

Inconel 713LC super alloy is one of the most widely used high-temperature alloys. Due to the high level of gamma prime phase caused by Ti and Al alloy more than a critical value, this alloy is considered as one of the non-weldable alloys. One of the basic repair methods of this series of superalloys is laser cladding methods. In this research, the IN713LC  substrate was reconstructed with Inconel 625 powder by a direct laser deposition system. To characterize, optical and electron microscopy tests, porosity measurement, and XRD were carried out; The results showed that the R (growth rate of the dendrite tip) increases at high speeds of laser cladding; as a result, the G/R (combined solidification point) ratio decreases, and the structure tends towards the coaxial dendritic direction. For this reason, by increasing the speed of laser scanning from 4 to 6 mm/s, the coaxial dendritic structure increases. The hardness measurement results indicate a decrease in the hardness up to the junction area from 430 to 370 Vickers and fluctuations of about 50 Vickers. Due to the high solidification speed, the average distance between the secondary dendritic arm space was 0.8 at the bottom, 1.01 in the middle, and 1.75 micrometers at the top of the sample. Due to the high cooling speed, only carbides and lava phases are formed. Also, the porosity measurement results of the cladding indicate a maximum porosity of 0.1 percent.

316 steel is used in transportation, space, and chemical equipment. This steel is in demand in these industries due to its durability. It is used to increase the lifespan and renovate equipment. The research explores the impact of laser energy density on st6 cladding. It specifically focuses on the microstructure and geometric characteristics of the cladding. The cladding is applied on 316 steel. The experiment was designed with energy density changes from 40 to 116 J/mm and powder rate changes between 12 and 20 g/min. Optical and electron microscopic images were used to evaluate the samples. The results indicated that the dendritic arms grew larger with increased energy density. The dimensions increased from 1.5 to approximately 3. In other words, the speed of cooling is doubled. Increasing energy density from 40 to 75 J/mm reduced cobalt to chromium ratio from 2 to 0.7. It also decreased cobalt to iron ratio from 35 to 3. The changes emphasize how energy density affects microstructure and phase transformations.