1. Selection principle of nickel and nickel alloy welding wire: Nickel and nickel alloy welding electrodes are mainly chosen according to the alloy grade, chemical composition and environment of the base metal. The main chemical composition of the deposited metal of the electrode should be close to the main component of the base metal to ensure that the performance of the welded joint is equal to that of the base metal. Some other elements should also be included in the electrode to improve weld performance or welding process performance.
2. Notes for the use of nickel and nickel alloy welding wires
① The parent material preparation: Before welding, the oil, paint, dust and other dirt on the base material should be carefully removed.
② In order to prevent the pores, the short arc welding is used.
③ It has smaller welding current, no preheating before welding, keep lower channel temperature (<150 DEG C) in order to avoid overheating of base material.
④ When welding, the swing of the welding rod should be small, and the sides of the welding bead will stay on both sides for a long time, so as to make the pores and welding slag emerge.
⑤ It should fill with arc crater, so as to avoid the crater crack.
⑥ The microstructure of nickel and nickel alloy is austenite and has a strong tendency of hot crack. When welding the fillet weld, the bead is raised, so that the thermal crack can be prevented.
