Thin steel is used for the manufacture of a variety of designs. At the enterprises, welding works are carried out using special apparatuses, which provide the products with optimal connection. How to cook thin metal with an electrode at home? What equipment work best? Such questions are asked by inexperienced welders who are forced to work at home. Information on how to properly weld thin metal with an electrode can be found in this article.
What are the difficulties?
The importance of the question of which electrodes is better to cook thin metal is due to the fact that if they are improperly selected or the work rules are not followed, the master may have problems. These include the following:
- Due to the fact that you have to work with fairly thin material, it is important to correctly calculate the current strength. Otherwise, several through holes may form in the metal. They are also the result of slow seam management.
- Trying to prevent burn-throughs, many welders are in a hurry too much, going through the joint. As a result, an undigested place remains on the treated surface. Specialists call such sites lack of fusion. As a result, the connection is obtained with poor tightness, and the product is considered unsuitable for working with liquid. In addition, the metal has a low rate of tensile and kink resistance.
- Often, those who do not know how to cook thin metal with an electrode make another mistake, namely, they leave inflows from the back of the connected products. If on the front side the surface looks normal, then on the back it leaves much to be desired. This can be prevented using special substrates. It is also desirable to reduce the current strength or change the welding technique.
- It happens that the structure is deformed. The reason is overheating of sheet steel. Since the metal structure remains cold at the very edges, and the intermolecular component expands at the weld point, waves begin to form on the surface of the steel, which leads to a general bending. According to experienced welders, the problem is solved by cold straightening - with the help of rubber hammers, the sheet is straightened. If this is not possible, then it will be necessary to alternate the correct sewing during welding.
To prevent these shortcomings, you need to know how to cook thin metal with an electrode.
About current sources
For welding, such sources can be transformers and inverters. According to experts, the first option is now considered long obsolete and will soon be abandoned. Despite the indisputable advantages (high reliability and endurance), transformers too draw down the power supply network, which often entails damage to the wiring and electrical equipment. Inverters, on the contrary, do not plant the network and, according to experts, will be an ideal option for a novice welder. If earlier, when working with a transformer source, the electrode stuck to the surface and burned the network, then the welding current is simply turned off with the inverter. At the very beginning of arc ignition, a current surge is observed on the transformer, which is undesirable. The situation is different with inverters - in these devices, thanks to the presence of special storage capacitors, the energy pumped earlier is used.
About Arc Welding
According to experienced craftsmen, the success of arc welding depends on the quality of the calcination of consumables. The optimal temperature is 170 degrees. In this thermal regime, uniform coating melting occurs. It is convenient to manipulate the arc, forming a seam. Welding electrodes for thin metal sheets must be with a high-quality coating. In accordance with the technology, an intermittent arc is formed by short-term separation from the electrodes from the weld pool. If the product has a refractory coating, then at its end a kind of “visor” will necessarily form, which will interfere with the contact and the creation of the arc.
About the cross section of the electrodes
According to experts, the power of the output current directly depends on what diameter the electrode has. For a thick one, a source is required that can provide a large amount of current. Thus, for a certain diameter, a specific power indicator is provided, beyond which it is impossible to go.
If it is deliberately underestimated, then the weld simply does not form. Instead, only metal streaks with slags and electrode coating will remain on the treated surface. For example, if you work with a 2.5 mm electrode, the minimum current indicator should be 80 amperes. Up to 110 amperes overstate it when they work with an electrode 3 mm thick. Judging by numerous reviews, the idea of performing welding work with electrodes with a cross section of 3 mm at a current rate of 70 amperes is initially a failure, since no seam will work.
Where to start?
Before you cook thin metal with an electrode, you need to choose it correctly. Due to the fact that you have to cook with a reduced voltage, it is not practical to use 4-5 mm electrodes. Otherwise, the electric arc will “stall” and burning will not be carried out fully. What electrodes to cook thin metal inverter? Judging by numerous reviews, the best option would be electrodes with a thickness of 2-3 mm.
What will experts advise?
Anyone who does not know how to cook thin metal with a 2 mm electrode should use the special calculation table. For a material whose thickness does not exceed 1 mm, a current of 10 A and 1 mm electrodes are used. Judging by the numerous reviews, they burn out quickly enough. If you have to work with a metal of 1 mm, the current strength indicator should vary from 25 to 35 A. For such welding, electrodes with a cross section of 1.6 mm will be needed. 2 mm is recommended for sheets with a thickness of 1.5 mm. The current strength in this case is higher and amounts to 45-55 A. Electrodes with a cross section of 2 mm are provided for a metal 2 mm thick. In this case, a current of 65 A is used. How to cook a thin metal with a 3 mm electrode? As experts recommend, a product with such a cross section works with metal 2.5 mm thick with a current strength of 75 A.
About Butt Joint
Due to the fact that they connect thin-sheet steel sheets to the joint, material is often burned. To prevent this, you need to correctly draw the edges of the plates. Most welders prefer to overlap plates. Thus, the base for the deposited metal will be formed, preventing it from burning. Nevertheless, many beginners are interested in how to weld thin metal with a 3 mm electrode to the joint? As experienced welders recommend, it is not necessary to cut their edges when placing the plates. There is also no need for a gap between them. It is enough only to bring the ends of the sheets to be welded closer together and tack them together. It will be easier to work in the mode of low current strength and with the help of relatively thin electrodes.
About Butt Welding
Butt welding is carried out in several ways:
- First, the unit is set to weak mode. The formation of the seam is carried out quickly and clearly along the seam line. In this case, oscillatory movements are not necessary.
- This method uses a slightly increased current. To form a seam, it is recommended to use an intermittent arc. This measure is due to give the material time to cool before a new “portion” of the additive is applied to it.
- The third method is practically no different from the previous one. However, in this case, welders use special substrates, the task of which is to maintain a heated area and prevent its failure. Judging by the reviews, it is undesirable to use a metal table as such a substrate. Otherwise, it will simply weld to the product itself. The best option is a graphite lining.
- Some masters practice staggered welds. This method prevents deformation of the structure. You can also place seams in small sections. To do this, they begin to form a new seam from the point at which the previous one ends. By means of this method, the product is uniformly heated to prevent its deformation.
Working process
Before welding, the parts to be joined are thoroughly cleaned from rust. Units that provide direct current are good because reverse polarity can be used for welding.
It is enough to insert the electrode into the holder, which is connected to the cable with the designation “+”, and the cable with “-” to the surface of the steel part. This method of connection will provide a large heating of the electrode, and the metal surface will warm up less. If the master pursues the goal of heating the connected products weaker, then they must be placed vertically. According to experts, it is important that they are inclined within 30-40 degrees. Cooking is carried out from top to bottom. The tip of the electrode should be moved in one direction without any deviations to the sides.
About Welding Galvanized Steel
This material is also called galvanization. It is a thin sheet of steel, which is coated with zinc. Before joining the edges, the coating is completely peeled off at this point in galvanizing. This can be done mechanically by means of an abrasive wheel, sandpaper or a metal brush.
A good coating is burned out by the welding machine. Due to the fact that zinc, evaporating at a temperature of 900 degrees, emits very toxic fumes, you need to perform these works in the fresh air or in well-ventilated areas. After each pass with the electrode, flux must be knocked down. When the zinc is completely removed from the surface, you can proceed directly to welding. Galvanized pipes are mainly connected by two passes with electrodes of different grades. For the first pass, products containing rutile coating are used. Well proven electrodes OZS-4, ANO-4 and MR-3. During welding, the oscillations by them should be carried out with a small amplitude. To form the upper facing seam, experts recommend the use of electrodes DSK-50 or UONI 13/55. The area of the last seam should be slightly wider.