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Welding method of argon arc welding

Operation methods of argon arc welding:

(1) Wire feeding: wire filling inside and wire filling outside. ?

the external filler wire can be used for priming and filling, which uses a large current, and its welding wire head is on the front of the groove, and the welding wire is pinched by the left hand and continuously fed into the molten pool for welding, and the groove gap is required to be small or no gap. ?

wire filling can only be used in backing weld. It is the wire feeding action with the thumb, index finger or middle finger of the left hand. The little finger and ring finger clamp the welding wire to control the direction, and the welding wire clings to the blunt edge inside the groove and melts with the blunt edge for welding. It is required that the gap between the groove is larger than the diameter of the welding wire. If it is a plate, the welding wire can be bent into an arc. ?

(2) welding handles can be divided into crank handles and mops. ?

the crank is to press the welding nozzle slightly on the welding seam, and shake the arm greatly for welding. Its advantages are good weld protection, good quality, beautiful appearance and high product qualification rate, especially convenient overhead welding, and very beautiful appearance color can be obtained when welding stainless steel. Its disadvantage is that it is difficult to learn. Because of the large swing of the arm, it is impossible to weld where there are obstacles. ?

The mop is that the welding nozzle gently leans or leans against the weld, and the little finger or ring finger of the right hand also leans or leans against the workpiece, and the arm swings slightly, dragging the welding handle for welding. Its advantages are easy to learn and good adaptability, but its disadvantages are that the forming and quality are not as good as that of the crank, especially the overhead welding without the crank is convenient for welding, and it is difficult to get the ideal color and forming when welding stainless steel. ?

(3) Arc striking

Arc striking generally adopts an arc striking device (high-frequency oscillator or high-frequency pulse generator). When there is no arc striking device, it adopts contact arc striking (mostly used for site installation, especially high-altitude installation), and red copper or graphite can be placed on the groove of the weldment to strike the arc. However, this method is more troublesome and less used. Generally, the weldment and tungsten electrode are lightly scratched with a welding wire. ?

(4) Welding

After the arc is ignited, preheat the weldment for 3-5 seconds, and start wire feeding after a molten pool is formed. When welding, the welding wire welding gun angle should be appropriate and the welding wire should be fed evenly. The welding torch should move forward smoothly, and swing from side to side slightly slower on both sides and slightly faster in the middle. Pay close attention to the change of molten pool. When the molten pool becomes larger, the weld becomes wider or sunken, the welding speed should be accelerated or the welding current should be reduced again. When the fusion of the molten pool is not good and the wire feeding feels immobile, it is necessary to reduce the welding speed or increase the welding current. If it is backing weld, the attention should be focused on the two blunt edges of the groove, and the corner of the eye is on the opposite side of the seam. Pay attention to the changes of the other heights. ?

(5) Arc closing

If the arc is closed directly, it is easy to cause shrinkage cavity. If there is an arc starter, the arc should be closed intermittently or adjusted to an appropriate arc closing current to slowly close the arc. If there is no arc starter welder, the arc should be slowly led to one side of the groove without shrinkage cavity. If shrinkage cavity occurs, it should be polished before welding. If the arc is closed at the joint, the joint to be closed should be polished into a bevel first, and then the joint should be fully melted before welding for 1-2 mm and then slowly closing the arc. Shrinkage is not allowed. In production, it is often seen that the joint is not polished into a bevel, but the welding time at the joint is directly prolonged, which is a very bad habit. In this way, the joint is prone to concave, the joint is not fused and the reverse side is out of line, which affects the beautiful shape. If it is a high alloy material, it is easy to crack.