Comparison of the Mechanical Properties of Ni 99.2 Thin Sheets Welded by Different Arc and Laser Welding Processes

Due to their corrosion resistance, nickel alloys are increasingly used in environmental and power engineering. Incorrect preparation, execution and finishing of welds on nickel alloys can lead to problems such as cracking, porosity or inclusions in the weld metal and heat affected zone. Nickel is prone to pore formation during welding, with a sharp change in the solubility of hydrogen and oxygen as the metal passes from the solid to the liquid state. In order to weld nickel alloys and nickel 99.2 sheet efficiently with predictable results, different welding processes need to be evaluated and optimized with respect to the influences that affect the welding process. A sound technical solution for the efficient and flawless welding of Ni 99.2 and nickel alloys must therefore be found. The following article presents an investigation of the influence of different seam preparations welded by different welding processes (beam welding, arc welding) to determine the most effective welding process for Ni 99.2 (2.4068) thin sheets. For this purpose, thin sheets with different edge preparations are produced for linear welding. In addition to the optical and mechanical properties, the microstructure of the weld is also investigated. The results show that it is possible to establish a stable and efficient welding process for Ni 99.2. Cross sections show dendrite growth towards the center of the seam. Preliminary tests show a dependence of the grain orientation on the welding speed. The influence of the grain orientation and the characteristic of the dendrite growth direction on the mechanical-technological properties of the welded material is investigated.