Nickel and nickel alloys, especially the temperature of commercially pure nickel and nickel-Copper Electrode alloy, the solid-liquid phase spacing is small, low liquidity. Under welding conditions of rapid cooling and solidification crystals, some of the gaseous components in the solid phase solubility is far lower than the liquid phase, vapor phase the late precipitated to form pores in the weld metal. Nickel and nickel alloy welding carbon steel and low alloy steel welding easier to form pores, especially in the oxidation resistance welding atmosphere, more likely to produce pores. Nickel and nickel alloy of the weld metal at high temperatures will react with oxygen forming NiO, steam generated during the cooling process, with the reaction of hydrogen dissolved in the metal, with the dissolved metals react with carbon monoxide (CO) is generated in the crystalline When these gases are often too late to escape the formation of pores. Especially when dissimilar metal welding is carried out in the nickel and Nickel Alloy Welding Wire and steel, tend to be higher due to the carbon content in the steel, the amount of carbon monoxide that may produce more, the formation of pores the sensitivity may be greater. In addition, the welding in a reducing atmosphere, may also be generated by the hydrogen stomatal sensitivity. Therefore before welding on the workpiece surface removal of oxide, water, organic matter can reduce blowholes possible. Containing manganese, titanium, aluminum and other elements in the weld metal can play a deoxidizing effect. Contains chromium, manganese can improve the solubility of the gas in the solid metal, to reduce the pores can also play a beneficial effect.
In order to prevent the generation of pores, you must eliminate the source of the stomata, groove and near the weld zone oxides, various coatings, grease, etc. must be removed before welding. Addition should be removed before welding of nickel and nickel alloy weldments moisture, organic matter, oxides, should pay special attention to the surface of the non-residual sulfur and leaded material to avoid weld welded joints in nickel with sulfur or lead role brittle.