1. Preparation and preheating of nickel base electrodes before welding: Clear the oil and oxidized skin around the defect, exposing the metal luster of the base: Open Groove, the general Groove depth is 2/3 of the wall thickness of the weld, the angle is 70°~120°, and the welding piece will be heated slowly to the 600~700℃ (no more than 700 ℃).
2. Welding: The use of neutral flame or weak carbon flame (welding process do not allow molten iron flow to one side), after the matrix metal melts, then melts into the electrode metal; When the white bright spot appears in the molten pool, stop filling the electrode metal, add the appropriate flux, remove the sundries with the nickel base electrode and then continue to apply the welding; to get the flat weld, Weld seam should be slightly higher than the surface of the cast iron, and will overflow in the weld slag remelting, to be cooled to a half melting state, with the wire along the surface of the casting will be higher part of the scraping.
3. After welding cooling: Generally should be cooled slowly to room temperature (generally more than 48h), can also be used asbestos cloth (plate) or carbon ash cover, so that the formation of uniform weld seam structure, while preventing the emergence of cracks.