Welding is the process of joining metals by establishing interatomic bonds between the parts to be welded during heating or plastic deformation. Various energy sources are used for welding: laser radiation, gas flame, friction, ultrasound. One of the popular welding methods is arc welding.
It is necessary
Welding machine, electrodes of various sections, chipping hammer, wire brush
Instructions
Step 1
Select a specific arc welding technique. In arc welding, various techniques and schemes for joining the parts to be welded are used: welding from the middle to the edges, welding in a reverse step, welding in blocks, cascade, "slide".
Step 2
For common "heap" welding at the base of the edges, lay the first seam, while its length should not be more than 300 mm. Then cover the first layer with the second, making its length 200 mm longer. Apply the third layer in the same way, which should also overlap the second by 200 mm. Continue filling until the number of layers in the area of the first joint is sufficient.
Step 3
If you laid the first seam in the middle part, and not at the beginning of the plane to be welded, then form the slide sequentially in both directions. The advantage of the described method is that the welding zone is constantly in a heated state, which improves the quality of the seam and prevents the appearance of cracks, because internal stresses in this case will be minimal.
Step 4
Perform the "cascade" method of welding parts, which is a modification of the "slide", in a different sequence. Connect the details together "on tacks". Place the first weld layer, back 300 mm from it, then add the second layer, which should cover the area of the first one. Keeping this "cascading" sequence, fill in the entire seam.
Step 5
When making fillet welds, you can use one of two welding methods. Corner welding allows for a significant gap between parts, which simplifies assembly, but complicates the welding process. In addition, the need to weld seams of small cross-section in one pass reduces the productivity of the welding process. The so-called boat welding is more productive, but requires careful assembly.
Step 6
The described techniques are good for welding at the lower seam positions. But when welding horizontal seams on a vertical surface or with overhead seams, there is a risk of molten metal flowing out. To carry out such welding work, it is necessary to reduce the welding current and use smaller electrodes. This solution makes it possible to use surface tension forces to hold the metal in the welding zone. In this case, the number of passes during seam execution increases.
Step 7
In addition to surface tension forces, use pulsed arc creation: do not hold the arc constantly, but at certain intervals (pulses). To do this, the arc must be interrupted constantly, allowing the molten metal to crystallize. The use of this method of arc welding requires high qualifications of the welder and experience.
Step 8
Remove the weld with a chipping hammer. Wait until the workpiece has cooled down, press it firmly against the table and remove the slag with a hammer blow. Then, forge the seam, which will relieve internal stress. Finally, clean the welded joint with a stiff wire brush, removing the last remaining slag.
