Definition of welding

Definition: The joining and homogenization of materials to each other using heat or without the help of pressure or additional fillers is called welding. The materials to be bonded are also called the base metal and the material that makes the bond is called the filler metal or the weld metal. In order to melt the base metal and the weld metal, heat is used to convert the materials into fluids and allow them to interfere. The most common method in welding structural steels is to use electrical energy as a heat source. For this reason, electric arcs are often used. An electric arc can be defined as the discharge of a large current between a weld metal (electrode or welding wire) and the base metal between a column of ionized material known as plasma. In this welding method, the process of melting and connecting with the material flow is done during the arc without applying pressure.

Types of welding include:

Arc welding Boiling point Non-ferrous metal welding Soldering Electric and gas welding Underwater welding Plastic welding

The history of welding, such as human needs, has required welding and welding in all cases, so for example, from the ancient Romans, a person named “Pliny” used solder called Argentarium and Ternarium, which had equal amounts of tin and lead, and Trinim had two parts. It was lead and a part of tin that are still used as fillers. And because the science of welding was accompanied by a specialized treasure, that is, every skilled welder had a large income throughout history, they caused them to hide their secrets from each other. For example, in the case of aluminum solders and alloys, they still keep it secret from each other. Welding made great strides during the First and Second World Wars. Human needs for modern – light – strong and durable connections in recent years, and especially in the last twenty years, have led to the rapid development of this technology, and huge investments have been made in this regard by both governments and military and specialized industries, especially human competition in science. The nucleus (which should be only for peace) has become another reason for the super-rapid development of this technique in the last few decades, which has become the science of welding.

Different welding groups

1 solder 2 pressure welding and pressing 3 melting welding 4 yellow welding

It is repeated that in specialized welding and basically all types of welding, the weldability of metals must be known exactly. Sufficient care must be taken with intermediates, electrodes and welding powder. The necessary environment must be created before, during and after welding, for example in the case of cast iron. The gases of suitable devices and the selection of suitable metals in terms of melting in the iron furnace and then during welding in terms of preventing damage to gas – fire and burner and electricity and ambient air and the physical condition and life of the welder are other basic points that are welding problems. . Welding is actually the establishment of a steel and metal plant with a maximum area of ​​2.2 meters and a critical welding point of a few centimeters, because the same temperature of the steel plant is created at the point of welding at one point. It is certain that such a huge work requires initiative, expertise, materials, expertise and modern equipment to be able to use this steel a few centimeters correctly. And non-technical is not necessary. Arc welding One of the most widely used and easiest methods for connecting structural steels is to use an arc welding method with an electrode. In this method, the required heat is generated by creating an electric arc between the coated electrode and the components to be connected. The coated electrode is used during welding by melting and transferring to the base metal. The metal of the electrode becomes a filler and part of the coating turns into a shielding gas and the other part into welding mud. The electrode coating consists of a mud-like mixture consisting of hardening silicates and other materials such as oxides, carbonates, fluorides, and metal and cellulose alloys. This mixture, when cooked and compressed, causes hardness, dryness and high density in the coating. The functions of the electrode coating are: • Forms a gas shield, separates the air and keeps the arch steady. • By adding other materials such as reducing agents to the weld metal, it improves its structural texture. • By forming a coating of welding mud on the pool of molten and hardened welding, in addition to protecting them from oxygen and nitrogen in the air, it also prevents rapid cooling of the weld. In addition to arc welding or manual electrodes, there are other methods of arc welding, which are often done automatically. These methods are: shielding with gas welding, welding with ballast welding wire and submerged arc welding. In these methods, the electrode is in the form of a continuous wire without coating and performs the coating operation using CO2 gas or powder. If you are interested in information on how to perform these welding methods and its details, you can refer to reputable specialized sources. Most mild steels are suitable for welding. While suitable values ​​for high-strength steels can exceed the ideal analytical limits in the table above.

Welding pliers

The device used to hold the electrode and perform welding is welding. The pliers are divided according to the current capacity they are able to pass. A very strong insulation material is covered on the pliers. Rubber, compressed fiber and rubber are among these insulators. The connection clamps are also attached to the base of the welding table or to a piece under welding. In addition to being clean, these clamps must also have a strong spring so that they adhere well to the table base or to the work. The next two images show welding and connection pliers, respectively.

Electrodes

The electrodes used in welding steel joints have alloy or non-alloy core wires that guide the welding current. The electric flame burns between the workpiece and the free electrode and the electrode melts as an additional material. Softened electrodes have the abbreviation (Dean 1913) written on the packaging. Abbreviations show all the important points that must be observed in using that electrode. Specifications of electrodes In welding, the specifications of the electrodes are determined by a series of numbers. The characteristic numbers are in the following order: E 60 10 = E Electric current 60 = Welding of pollen in pounds per square inch 1 = Different welding situations 0 = is the type of flow The first sign In the above electrode markings, E indicates that this electrode is for electric welding and is used. (Some coated electrodes are used in welding with oxyacetylene) The second sign The number 6 and 0 means that the tensile pressure of the weld is in pounds per square inch, it must be multiplied by 1000, that is, the tensile pressure of this type of electrode is 60,000 pounds per square inch. The third sign Indicates boils that are always 1, 2, or 3, their third sign The fourth sign The appearance characteristics of the pollen and the type of flow determine that these symptoms start from 0 and end in 6.