2. Both ends of the butt joint shall be provided with arc striking plates and arc extinguishing plates with appropriate sizes. Be sure to clean the dirt in the hose and the splash from the nozzle. For plate joints with grooves, especially thick plate multi-pass welding, the welding wire should stay on both sides of the groove for a short time when swinging, and the thickness of each layer of sawtooth strip should not be greater than 4mm, so as to make the weld fusion good.
3, according to the diameter of the welding wire, choose the welding wire contact correctly, and the length of the welding wire should generally be controlled within 10 times of the welding wire diameter. When welding, the wire feeding hose must be pulled smoothly and cannot be bent. The radius of the wire feeding hose shall not be less than150 mm. Before welding, the residual impure gas in the gas supply hose shall be discharged. After the contact nozzle is worn, the aperture increases, which leads to unstable welding and needs to be replaced again.