Due to the different sizes of stainless steel pipe fittings, according to the unique welding of stainless steel pipe fittings, the heat input is reduced as much as possible, so manual arc welding and argon arc welding are used. Arc welding cover surface. All argon arc welding for d≦Φ159 mm. The welding technical requirements for stainless steel pipe fittings are as follows:
1. When manual arc welding, the welding machine adopts DC reverse connection, and when argon arc welding adopts direct current connection;
2. For argon arc welding, the nozzle diameter is Φ2 mm, and the tungsten electrode is Φ2.5 mm;
Stainless steel pipe fittings
3. Clean up the oil stains within 25 mm on both sides of the groove of the workpiece before welding, and wash the 25 mm on both sides of the groove with acetone;
4. Before welding, the welding wire should be brushed off with stainless steel wire to remove the oxide scale on the surface, and washed with acetone; the welding rod should be dried at 200-250℃ for 1 hour, and used as needed
5. When welding stainless steel by argon arc welding, the back side must be filled with argon gas to protect the back surface. Using the method of partially filling argon in the pipeline, the flow rate is 5-14L/min, and the front argon flow rate is 12-13L/min.
The thickness of the welding seam should be as thin as possible during the bottom welding, and the fusion with the root should be excellent, and the arc should be in a gentle slope shape when the arc is closed. The arc must be ignited and extinguished in the groove, and the crater should be filled when extinguishing the arc to prevent the crater from cracking.
