Devices for electric arc welding today are available to almost everyone. Many acquire a wide variety of product samples to facilitate the manufacture and assembly of various metal structures made of metal. Some have the necessary skills to do this, others want to learn how to learn how to weld metal.
Scheme of electric arc welding.
In one small story it is impossible to describe all the nuances of this fascinating business, as skillful welders are trained not one month, but real skill comes to them through experience. The welder will learn to make skillful seams only in a few years. Nevertheless, it is worth giving a few recommendations that will help home craftsmen learn how to weld at least at the elementary level. Knowing some rules for handling electrodes and a welding machine, amateur welders can already make a fence, a shed, a wicket or gate.
What are electrodes?
Having learned the wisdom of the profession, experts can determine the type of electrode, only glancing at it. In the future, this knowledge could not have prevented nonprofessionals, but for the time being they need to be given preliminary information about the electrodes used for metal fusion. There are only about 10 types:
Electrode position when welding parts.
- Cores for welding low alloy steel and high carbon steel.
- Electrodes for connecting high-alloy steels.
- Electrodes for welding thermostable metals.
- Rods for welding cast iron products.
- Electrodes for cladding (this operation is performed during the restoration of metal surfaces).
In addition, there are electrodes that are designed specifically for cutting metals, joining non-ferrous and non-uniform metals, as well as welding various alloys.
All electrodes are the same. Their core envelops a protective coating that supports the burning of the welding arc and creates an oxidation-free zone in the weld area. The coating does not completely cover the rod. One end is bare to ensure the creation of an arc when in contact with the surface, the other side is cleared of a few centimeters to attach the electrode to the holder. The cores are made of different grades of steel and even polymers, and their plastering is made from calcium fluoride, mineral acid and rutile compositions.Back to table of contents
What diameter to choose?
Patterns of movement of the electrodes during welding.
In order not to burn the welded metal, you need to be able to properly select the electrodes. Their cross-section should be directly proportional to the thickness of the edges being joined.
- 2-mm sheets or products with walls up to 2 mm are fused with rods with a section from 1.5 to 2 mm.
- 2.5 mm or 3 mm rods are suitable for metal thickness of 3 mm.
- Thickness is 4-5 mm - the section is 3 or 4 mm.
- Sheets from 6 to 8 mm are fused with 4 mm electrodes.
- 9-12 mm - diameter 4 and 5 mm.
- 13-15 mm - the cross-section of the rod is 5 mm.
By the way, the thickness of the electrode is determined by the cross section of the steel rod.Back to table of contents
How to adjust the welding current?
The mistake that novice welders make is that they cannot select the strength of the current for welding. It directly depends on what electrode rod is used and what operation with steel will be performed. Below are the ranges of current, corresponding to the normal operation of electrodes of different thickness.
Table selection of current for welding.
It is worth adding that the maximum values indicate the cutting current of the metal, and the minimum values indicate the current for its welding. In practice, they may differ slightly, but the deviations (small) are caused by the characteristics of individual welding machines. The optimal range is selected within the specified values. If the current is below the required minimum, then it will not work, as the electrode rod, in contact with the surface to be welded, will spark only sparks. At a current exceeding the allowable maximum, the steel will be melted and burned.
Here is a table of the cross section and current:
- 1.5 mm - 30-60 A;
- 2 mm - 30-80 A;
- 2.5 mm - 50-110 A;
- 3 mm - 70-130 A;
- 4 mm - 110-170 A;
- 5 mm - 150-220 A.
Back to table of contents
In everyday life, electrodes with a cross section of 2 to 4 mm are mainly used, so the choice of welding machines must be made taking this factor into account.
How to hold and drive the electrode rod
The process of argon metal welding.
Welding metal with high quality means not only choosing the right current and the cross section of a rod. It is also necessary to be able to correctly guide the rod along the seam, to keep it at the required angle and not to allow overheating of the joints or premature attenuation of the arc. The initial touch of the rod to the edges to be welded should be similar to a light tapping or striking a fire with a match. After the formation of the arc, the electrode does not need to be pressed to the surfaces to be welded. The distance between its tip and the metal should be from 2 to 5 mm. Gradually (and rather quickly) you will learn to maintain the necessary gap so that the rod does not stick and the arc does not extinguish.
The welder’s hand should be relaxed. This will allow to lead the electrode not in a straight line, but with light wave-like movements (just as a pastry chef puts cream on a cake), then the adjacent surfaces will not just be red-hot, but reliably fused with each other. Practice driving the rod without turning on the device. Touch them to steel, slightly pull back your hand, lead an electrode along an imaginary seam. Keep the electrode in a plane perpendicular to the steel sheet, but relative to the seam, the rod should be deflected from the perpendicular by 10-15 degrees.Back to table of contents
Perhaps you have learned how to use the holder correctly, have connected the “mass”, have correctly adjusted the current and have chosen an electrode rod of the desired cross section, and electric welding does not go (the electrode sticks, there is a lot of scale). This is due to dampening of the plaster. Enterprises producing electrodes, provide drying.
The scheme of the welding electrode.
Sometimes they are sold in moisture-proof packages, but opened bags are no longer an obstacle to dampness, and packs can be stored in the house or in a warehouse for a long time. Even with normal atmospheric humidity, the coating gradually absorbs moisture.
Dry the electrodes by burning them in the oven. Some packs indicate the time of this operation. Different electrodes need different drying times. It can last from 1 hour to 5, and its temperature ranges from 250 to 350 degrees. For most products, an hour and 350 degrees of calcination before welding are enough to lose the interfering work of moisture.
This temperature is maintained by electric and gas ovens. It remains to obtain permission for their use from the housewife of the domestic food unit. Perhaps, this stage in the drying of the plastering will be the most difficult, since the pleasant smell of heated metal and a slight smell in the kitchen is unlikely for a woman to smell men. Heat the electrodes immediately before work, and keep the rods remaining after it in polyethylene, since the coating of the nasty “habit” of the greedy absorption of moisture will never get rid of.
It remains to say that high-quality welding can be carried out only at the joints, the gap between which is minimal. The surfaces to be welded must be rust free. They should not be moisture. The seams before applying a new layer on them should be descaled. A novice welder is better to buy a mask "Chameleon", which will save his eyesight. Clothing should be tightly buttoned, pants should cover thick boots or boots. The use of clothing made of synthetic fabrics is not allowed.