Nickel and nickel alloy electrodes

Nickel and nickel alloy electrodes

Electrodes with nickel and nickel alloys as deposited metal,according to its composition system, they are divided into pure nickel, nickel-copper, nickel-molybdenum, nickel-chromium-iron and nickel-chromium-molybdenum. Each composition contains multiple grades. In particular, nickel-chromium-molybdenum-based electrodes have nearly 10 grades. The chemical composition of each grade varies. The coating types of the electrodes are mainly alkaline low hydrogen type and titanium calcium type. To eliminate welding porosity, most nickel-based electrodes in China are alkaline, low-hydrogen type, and contain appropriate amounts of deoxidizers such as aluminum, titanium, magnesium, and manganese. In order to prevent the occurrence of welding hot cracks, the content of impurities such as sulfur and lead in the weld must be strictly limited, and dirt, paint, dust, and other contaminants on the surface of the parent metal must be carefully cleaned before welding. Nickel and nickel alloys have poor thermal conductivity and are prone to overheating during welding, causing grain growth. Therefore, a small current should be used, the electrode should not be laterally oscillated as much as possible, and the temperature between the layers should be controlled less. This type of electrode is mainly used for welding nickel and high nickel alloys, but also for welding and surfacing of dissimilar metals. Welds and surfacing metals have excellent heat and corrosion resistance and are widely used in nuclear reactors, pressure vessels, and surfacing of sealing surfaces.