Perhaps, today there is not a single person who would not have to deal with welding. They densely enter into our everyday life. But practically no one has the skills and experience of work as a welder. It is quite natural to ask the question: how to weld metal with your own hands? To solve such a problem, it is necessary, first of all, to buy a welding machine, it will help to solve a variety of household chores.
The device of the welding machine.
To understand how to weld metal correctly, you must first get acquainted with some theoretical tenets. Why is welding considered a reliable connection, what is the basis of this statement? The strength of the weld is much higher than any joint. When metal parts are heated by an electric arc, plastic alloy deformation occurs. Electrode particles begin to penetrate into the metal of the welded parts, resulting in the formation of particularly strong intermolecular bonds. So it turns out indissoluble connection.
Submerged arc welding scheme.
Any welding is the highest strength of the connection of metal parts. The latest technology makes it possible today to carry out welding work with laser radiation. You can weld metal using ultrasound, using a gas flame. In most cases, the source of energy becomes an electric arc, which creates a welding unit or inverter installation.
For domestic needs, you can use any welding device, the maximum current of which reaches 160 A. The functioning of the welding machine is based on the principle of obtaining a welding arc between the electrode and the surface of the part. In this regard, high-quality welding will be obtained only if the basic rules for the appearance of an electric arc are observed.
For the work you need to connect the transformer wire with the workpiece. Another wire connected to the electrode holder, through the electrode touch the surface where the welding will take place. After the metal is touched by the electrode, the arc is excited. Under the action of the arc, the metal begins to melt. The melt fills all cavities formed by melting of the metal surface.
Welding with consumable electrode.
For such work, the most important is the correct selection of the electrode. To do this, it is very important to know what chemical elements the metal consists of, which must be welded. Electrodes are made from:
- cast iron;
In addition, it can be bimetallic. When choosing an electrode it is necessary to familiarize yourself with its marking. It shows all its main parameters. The main and most important rule that must be strictly followed, the diameter of the electrode should be equal to the thickness of the metal.Back to table of contents
Electrode position during welding.
For arc welding, consumable electrodes are used. Through them to the seam is supplied with electric current. For semi-automatic welding, the main component is sometimes cored wire. It is fed automatically to the welding area. For beginners, it is better to start learning from electrodes that have a solid rod coated with a special compound. It will help you quickly gain experience and skills in order to obtain an accurate, fairly even weld.
The best to begin with are electrodes with a diameter of 3 mm. To conduct operations with large-diameter electrodes, it is necessary to have equipment with higher power. To cook thin parts, apply electrodes with a diameter of less than 2 mm. For work, you should always use only fresh electrodes; old and damp ones can be thrown away.
To get a stable and normal arc, you need to set the appropriate amperage. If the current is small, sticking will start to occur, and the arc will go out. With a large current, the metal will burn, it will spray in different directions.
Tools that you need to have for the welding process:
- welding device;
- protective mask;
- welding robe;
Friction welding process diagram.
Without the use of a protective mask it is impossible to perform welding. It protects the welder's eyes from the powerful ultraviolet radiation that occurs during the arc. Looking closely at an electric arc without a mask or glasses is strictly prohibited. The consequences can be the most deplorable: corneal burn and loss of vision. If you still had to look at a bright flash, you should put a cold compress on the eyes of a grated potato.
To protect hands, use special gloves, which are made from a special thick fabric. Masters call them "poddergushi." Such gloves will not allow splashes of molten metal to get on your hands. Special clothes are worn on the body, “robe”, made of thick fire-resistant fabric.
Wearing welding clothing, taking up the electrode, you can perform welding work. An electrode is inserted into the holder. From practical experience it is known that it is easiest to begin work with an electrode 3 mm thick, with a current of 120 A. To set the current, each welding machine is equipped with a special regulator. The current depends on the diameter of the electrode.Back to table of contents
Features of the welding process
Diagram of the process of cold welding.
When it is necessary to weld two parts, various types of welding joints are used. For example, butt joints are divided into 32 species. But four remain the most basic ones:
- butt joint
When the thickness of the metal exceeds 3 mm, it is necessary to process the edges of the part before welding. This will give the opportunity to get a seam that runs smoothly through the entire thickness of the part. Such processing of the ends allows you to cook a part with several layers having a small cross section. As a result, the voltage decreases, the structure of the welding joint improves.
Edge processing can be done at an angle. Its value can be very different. It all depends on the thickness of the metal being welded, the type of connection and the strength of the weld. This cutting can be done in the garage using emery. For cutting parts of large dimensions, you can use a gas cutter. Sometimes cutting is not possible, then for better welding of the metal, they specifically increase the strength of the welding current.
In order to light a spark, it is necessary to drive an electrode along the seam. If a spark occurs, the electrode must be raised a few millimeters above the surface - an electric arc will appear. So that it does not disappear, it is necessary to keep the electrode at the same distance. If the metal is already heated, then ignite the arc much easier. This process is not immediately. It will take some time and skill. When the electrode sticks to the metal, in order to tear it off, it is necessary to tilt the electrode slightly, and this should be done very quickly in order to prevent the welding machine from getting very hot. If you just try to pull the electrode up, it will exit the holder.
To cook parts, you need to slowly move the electrode along the entire weld so that the metal melts from below and above. In order for the seam to look beautiful and durable, you need to have a small gap between the parts. The movement of the electrode during welding is in the form of a zigzag. At this time, the metal will fall into the gap and will not extend beyond the surface. It will look smooth, beautiful and reliable.
Do not set too much current. Thus it is possible to burn metal through. The strength of the current must be such that no sticking of the electrode occurs. After welding, dross is lost from the seam. The seam is exposed and it is possible to check its strength.Back to table of contents
The scheme of welding thin metal.
Welding can be performed with a variety of tools. Masters and professionals use the inverter unit. It is quite clear that many are trying to learn how to work with such a device, what basic rules should be followed.
Details of a large thickness to cook is quite simple, but much more difficult when it becomes necessary to weld a very thin metal. For this, it is necessary to have electrodes of small diameter and small welding currents. This is exactly the kind of work that a welding inverter can do. It is only necessary to choose the correct electrode thickness.
Most often 4 mm electrodes are used. To get a strong and high-quality welding, you can not allow the metal to burn. The most correct seam, which is easiest to do, is a horizontal seam. To obtain it you need to make a seam in the form of a figure eight.
The resulting slag, after welding, must be removed. This work is performed only after the formation of the entire seam. The main task, when the work is carried out using an inverter, is to connect the two ends of the metal, which must be melted.
After receiving the first seam, using an inverter, you must carefully check the absence of voids. Each void is welded by welding wire.
To remove the previous welding using a variety of tools. Virtually fit any. The most commonly used grinder. Similar to other welding machines, the inverter requires the welder to fully comply with safety regulations.
For the inverter is very important the correct selection of electrodes.
This greatly affects the quality of the device. Carbon electrodes are best suited for welding low-alloy steels. For alloyed steels, alloyed electrodes are used, for surfacing - high-alloyed.
The type of work also affects the selection of electrodes. When welding at home or in the country most often used electrodes such as MR-3. For executing complex operations, the OUNI is ideal.