Mirror welding operation method, the original details are full.

【Summary Description】 Mirror welding operation method (1) Bottom welding A. Internal thread adding method Fix the welding torch in the welding arc starting area to start the arc, and the welding wire is delivered to the post-arc through the front groove gap. Observe the formation of the root with the naked eye, and observe the internal arc and appearance of the lens from time to time. Use the "two slow and one fast" method to operate the welding gun. Control the thickness of the bottom layer to 2.5~3.0mm .. 6 to 9 o'clock welding, and then 6 to 3 o'clock welding. The bottom layer soldering is completed in the sequence shown in FIG. 2. B. External filament method The arc consumed by the prefabricated welding wire, and then the welding gun is fixed on the nozzle weld at an angle of 60 degrees to start the arc. Note the arc in the lens and the wire feed in the molten pool. The wire feeding can be continuous or broken. The reflection of the lens is very easy to mislead the operation: for example, it is difficult to distinguish the welding wire in the real object from the welding wire reflected in the lens, which can easily lead to defects such as too high temperature of the molten pool, tungsten collision, pores, depression, etc. Therefore, the operation is to concentrate on the mirror, consciously hook the arc of the welding wire with the groove, and feed the wire evenly. The welding gun operates in a "two slow and one fast" mode, and the angle of the welding gun is adjusted according to the arc in the lens. Avoid the arc too long and the bottom layer too thick caused by the angle of the welding gun, and prevent the occurrence of defects such as incomplete welding. When welding to the position between 8 o'clock and 9 o'clock, you can see a part of the actual arc, and operate in combination with the physical and mirror conditions. Finish 1/4 of the nozzle weld before starting the mirror welding of the other 1/4 of the weld. The 6-point joint is one of the important operations of mirror welding, and defects are prone to appear in the opposite direction. During operation, in order to ensure the quality of the joint, the arc should be started at about 8~10mm of the front weld, and then the arc should be stably brought to the joint at 6 o'clock of the front weld. When the weld pool is formed at the joint, the welding wire should be added for normal mirror welding operation. Finally, complete the front (non-mirror welding) underwelding in the order shown in Figure 2, and complete the sealing. (2) Welding of overlay 1) Difficulty analysis Since the position of the weld in the mirror is opposite to the actual position, undercut, groove edge incomplete fusion, internal interlayer incomplete fusion, porosity or tungsten electrode damage during operation are prone to occur. 2) Operation requirements for cover welding Before welding, it is necessary to simulate the running track of the welding torch, adjust the angle of the lens and the arc curvature of the prefabricated welding wire. During welding operation, the welding muzzle shall be aligned with the groove at 6 o'clock for arc preheating. After preheating, with the brightness of the arc, the prefabricated arc welding wire is extended from the tube side to the position where the arc burns in the lens, and the wire is fed. The best wire feeding method is to slowly hook the arc-curved welding wire into the weld of the pipe and feed the wire into the molten pool continuously and evenly, and observe the growth process of the weld edge and the droplet transition and the arc length of the tungsten electrode in the lens. Press "two slow and one fast" and then move the lens to the other 1/4 of the weld on the back to adjust and fix the trajectory simulation. Improper operation of the 6-point interface can also cause welding defects, and it is a defective dense section. It is best to start the arc heating of the weld before 6 o'clock. When the joint melts into a puddle, the wire is added for normal mirror welding operations. Note the edge of the melting, according to the first section of the method of operation, until 3 o'clock arc extinguished. Then, the welded portions are welded in accordance with the regular method, thereby completing the welding of the covering layer of the entire pipe. 5. Preventive measures The mirror placement technique is very important. The farther the lens is from the object or the less parallel it is to the object, the greater the accuracy of the operation. ② The farther the lens and physical objects are from the operator, the more difficult the operation is; ③ Strictly control the gap between the pairs, the angle of the welding torch should be appropriate, the welding should be carried out in order, and the wire in the mirror should be clear.

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Mirror welding process, as well as difficult analysis.