Welding pithy of welder
Issuing time:2020-05-26 10:42
1. Flat welding
Listen to see two points to remember clearly, welding specification should be moderate.
Short arc welding is the key and the arc period should be shortened. The welding speed should be uniform, and the weld pool should be elliptical.
The arc crater should be filled and enough hot metal should be provided with anti shrinkage hole.
1) If you hear the "puff" sound, it means that the arc has been punctured immediately;
2) "Look" is to see the temperature and shape change of molten pool. The temperature and shape of molten pool determine the width, reinforcement and forming of back weld. If the bath temperature is too high and the weld hole is too large, the back weld is not beautiful and easy to burn through. If the temperature of molten pool is too low and the weld hole is too small, the root fusion is not good or even incomplete. Generally, the weld pool is oval, and it is better to melt through 0.5-1 mm on both sides of the groove.
2. Vertical welding
The size of molten pool should be appropriate and molten iron should be distinguished. Enough hot metal should be supplied to prevent shrinkage hole on the back. The movement of strip transportation should be flexible and the sound of electric arc should be heard at the joint. Both sides of the groove shall be well fused to prevent defects and ensure forming.
1) In vertical welding, due to the influence of gravity, the molten pool metal is easy to flow down, so the size of molten pool should be controlled properly;
2) In order to avoid forming "convex" shape of backing weld, forming an angle between groove and weld bead, resulting in slag inclusion and affecting the welding of filling and covering layer, the welding rod must be properly retained when transported to both sides of the groove to ensure good fusion on both sides of the groove.
3. Horizontal welding and overhead welding
One arc top can be used, and the perforation is forming; the arc extinguishing hook is welded horizontally, and the top up welding is upward.
1) "One arc top dual purpose": in order to realize the purpose of one side welding and two sides forming, welding arc must be used on both sides of front and back, generally 2 / 3 of them burn in front and 1 / 3 in back;
2) "Piercing is forming": only when the arc breaks through the blunt edge to form a weld hole, can the back side be formed;
3) "Transverse welding arc extinguishing hook" means that the welding rod strikes the arc at the upper side of the groove root during transverse welding, and then it is inclined to pull to the lower side of the groove root after melting the upper blunt edge to form a complete molten pool. This process is called back hook, which is repeated until the welding of the whole weld is completed;
4) "Overhead welding upward" means that after the overhead welding arc striking, an upward jacking force is quickly given to the welding rod to lower the arc to melt the blunt edge, which not only ensures that the groove is filled with molten iron to prevent back collapse, but also prevents the front molten iron from flowing down to form weld bead.
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