Welding of nickel alloys is fraught with significant difficulties due to their special physical and chemical properties - high propensity for pore formation with a sharp change in solubility of nitrogen, hydrogen and oxygen in the process of metal transition from the solid to the liquid state. In arc welding of high-purity nickel in argon the main source of pores is nitrogen, which dissolves in large quantities in the liquid metal and almost insoluble in the solid nickel.

To obtain pore-free welds an important condition is the purity of the surface of the electrode wire, welded edges, welding consumables and base metal (electrode coatings, fluxes, shielding gases), as well as binding of hydrogen and deoxidation in the process of welding nickel. This is solved by the introduction of strong deoxidants in the weld pool (titanium, aluminum, etc.), as well as the use of coatings or fluxes that can convert hydrogen into stable volatile HP compounds or bind nickel oxides. For this reason, the welding technology can provide reliable protection of the welded area from atmospheric air, degassing of the weld pool and good deoxidation. An effective measure to prevent porosity is welding with a short arc (up to 1.5 mm), which significantly reduces the flow of gases from the atmosphere.

Nickel's high propensity for crystallization cracks is due to the formation of large grains at the boundaries, which have a transcrystalline structure. To prevent the occurrence of cracks in the base metal, as well as in the weld, it is necessary to limit the content of harmful impurities and introduce elements that bind sulfur in the most refractory compounds: up to 0.1% Mg and up to 5% Mn.

When developing the welding technology, the main attention is paid to ensuring the required performance properties of the joints. The technology can be completely different even for the same alloy. When arc welding nickel alloys and nickel, it is not necessary to achieve the same chemical composition of the weld as that of the base metal, since even a perfect match does not avoid cracks, pores , etc. defects. In order to obtain the required weld properties and prevent defects, it is possible to resort to complex alloying.