Nickel and monel materials welding

Nickel and nickel and copper alloy named monel is one of the most important materials that is used in some industrial areas. In this study, pure nickel plates were welded by shielded arc welding and gas tungsten arc welding (GTAW) methods. Monel plates were also welded by gas tungsten arc welding method. All those weldments were carried out on but joined and flat position. Nickel casting shielded electrode was used for arc welding of nickel. On the other hand, naked nickel electrode and ER NiCu7 monel filler materials were used for the GTAW method. Argon and argon+%5H2 were used as shielding gases. In this study, the effect of the compositions shielding gas and filler materials, travel speeds on the mechanical properties of the weldments were investigated. Various characterization techniques such as, tensile testing, bending testing and microhardness measurements have been carried out and Charpy impact test were applied on monel weldments at various temperatures. Parallel microstructural studies were carried out on welded work pieces. Basic microstructural investigations were performed using optical microscopy with the techniques of light area and dark areas. Both detailed microstructural studies and fracture surface morphologies were also carried out using scanning electron microscope (SEM) with the techniques of point and linear elemental energy dispersive spectroscopy (EDS) analysis. It is seen from the results obtained in the experimental work that welding methods and parameter used in this study have an effect on microstructures and mechanical properties such as tensile strength and microhardness values of the nickel weldments. On the other hand, gas composition and number of passes have a little effect on the mechanical properties of the monel weldments.Key words: Nickel, Monel, GTAW, Welding, Mechanical properties, Microstructure