In this research, dissimilar point resistance connection of Hastelloy X nickel-based superalloy to X750 nickel-based superalloy was performed. For this purpose, the welding current in the range of 5.8-5.5 KA and the welding time in the range of 7-13 cycles, while other cities including the electrode force (6 KN) were constant. With the help of mechanical tests (peeling test) and cutting tension, optimal welding lines (time and welding current) were determined. Optical and electron microscopes are used in order to use different methods. On the other hand, tensile-shear test was used to study the mechanical properties including fracture energy, fracture strength and elongation. The hardness of different connection areas was eva‎luated using a microhardness measuring device. With the help of light microscopic images of the joints area, it can be seen that columnar and dendritic solidification mechanism dominates the solidification process in the welding area. In other words, columnar grains grow from the side of the heat-affected area towards the center line of the weld. By measuring the microhardness of different weld areas, the hardness (about 300 HV) is obtained for the weld metal that was connected with a current of 8.5 kiloamperes and a time of 10 cycles. The mechanical properties of the welding samples are shown that the more the welding time increases in a constant current, the intensity of the input heat increases, and this process increases the strength of the welding pressures before the melt is sprayed. This was also true for increasing the welding current at a constant time. With the excessive increase of welding steels, the intensity of the input heat was overpowered in the melt spraying and the reduction of strength happened. Result In terms of welding strength, the optimal lines in this research were determined by 6.5 KA current values and 13 cycle time and 6 KN electrode force. But taking into account both the strength and the increase in the length of the optimal lines, it is related to the connection made with the current values of 5.8 KA and the time of 10 cycles and the force of the 6 KN electrode. Examining the fracture surface of the same sample (current 8.5 kA and 10 cycle time) indicates the presence of dimples in the fracture surfaces, which is deformation and soft fracture mechanism.

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عبدالمجيد اسلامي , علي شفيعي