Few Welding Tips

       

In manual arc welding, the welding machine adopts DC reverse connection, while in argon arc welding, DC Forward connection is adopted;

Before welding, the oxide scale on the surface of welding wire should be brushed off with stainless steel wire and cleaned with acetone. The welding rod should be dried at 200-250 ℃ for 1hour and used as it is taken;

Before welding, clean the oil stain within 25 mm on both sides of the groove, and clean the oil stain within 25 mm on both sides of the groove with acetone;

In argon arc welding, the diameter of nozzle Φ 2mm, tungsten electrode is cerium tungsten electrode, specification Φ 2.0mm. When argon arc welding stainless steel, the back must be filled with argon gas for protection, so as to ensure the back forming. The flow rate is 5-14l / min, and the front flow rate is 12-13l / min.

be careful

When backing welding, the thickness of the weld should be as thin as possible, and it should be well fused with the root. When stopping the arc, it should be in a gentle slope shape. If there are shrinkage holes in the arc, it should be polished off with a grinder. The arc must be started and extinguished in the groove, and the arc pit shall be filled to prevent the crack of the arc pit.

To prevent carbide precipitation sensitization and intergranular corrosion, the interlayer temperature and cooling rate after welding should be strictly controlled. It is required that the interlayer temperature should be controlled below 60 ℃ during welding, water cooling must be carried out immediately after welding, and segmented welding should be adopted at the same time. The specific segmentation method is shown in Figure 2. This symmetrical and dispersed welding sequence can not only increase the cooling rate of the joint, but also reduce the welding stress.