It is not easy to prepare for arc cold welding of. Welding workers should eliminate debris such as oil fouling, incrustation, paint, dirt and oxide. Then they need to crack stop holes in 3 mm to 5 mm at both ends of the crack after checking the position and direction of crack. The open groove at the bottom of the tank should be circular arc form. If the thickness of the casting parts is within 15 mm, workers can open into a V groove with angle between 60 ° and 70 °. To get safer and more effective operation, the depth of the groove is about two-thirds of the casting parts thickness. If the thickness of the iron parts is over 15 mm, workers should open into X groove. when one side of casting parts cannot be welded, it also need to be driven into a v-shaped breach.
Electric current affects the welding quality. If the current is greater, the amount of carbon into the molten pool in casting parts will increase which makes the welding joint brittle and hard. And there will be a thick layer of white near the fusion line which may easily produce cracks.