1. Basic requirements for nickel rod welding

For the extension of nickel rods, in order to ensure that the composition of the nickel rods remains unchanged during the extension process, it is generally necessary to use tungsten arc welding for autogenous welding. The author once welded and processed nickel rods with a total length of 3m and one or two welding joints for a metallurgical enterprise. Due to the large cross-section and large mass of the nickel rod, large penetration depth is required during welding to prevent the entire connecting part from falling off due to insufficient weld strength during the electroslag smelting process, causing interruption of the smelting process.

2. Physical properties and weldability of nickel

Nickel has low chemical activity, and the oxide film formed in the early stages of oxidation can prevent further oxidation of nickel. Therefore, the protection of the weld seam and heat-affected zone during welding is not very demanding, and the flow rate of the shielding gas can be selected according to the flow rate during welding of low carbon steel. The physical properties of nickel and iron are close, but nickel has poor liquid fluidity [2]. Due to the large size of the weldment, the cooling rate is fast, and the welding process has no special requirements for the quality of the weld structure, so larger welding parameters can be used for welding.

3. Processing and assembly of nickel rod welding joints

Before welding the nickel rod, the cast end needs to be properly processed. Because nickel is very expensive, the end is generally not cut. The flash edge of the end is just hammered flat with a hammer or arc melted to ensure the joints. The gap is within 5mm. Select two nickel rods with the same cross-section for pairing. You can place the two nickel rods on regular 50 mm >50 mm angle steel and perform tack welding first to ensure concentricity.