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The different types of welding processes are: -Oxy – Fuel Gas Welding -Arc Welding -Resistance Welding -Solid State Welding -Thermite Welding -Radiant Energy Welding Selection of Welding Processes: Within Welding, there are various types of processes to choose from. These were developed over time to suit several types of materials and joining them together. Each process differs dependant on the size, density and thickness of the material. So, one maybe good for thin/ low density materials, whereas others may be good for thicker/ denser materials. Welding processes with their area of use are given below.
Resistance Welding refers to processes like spot welding that provides an extremely high current of electricity creating a lot of heat, this process holds 2 pieces of work together under pressure and are exerted by electrodes.
Thermite Welding is when you employ molten metal to permanently join the conductors on a railway track. This process is an exothermic reaction with thermal energy being created as a result of the reaction. Therefore, this doesn’t need and outside source to provide energy to create heat of a thermite composition.
Oxy – Gas Welding refers to when you’d employ fuel gases and oxygen (oxyacetylene) to either cut or joint metals together. Interestingly, during 1903, 2 French engineers developed this method of Welding.
Submerged Arc Welding is when the formation of an arc between a wire electrode and the work piece occur. This process uses flux to create a protective gas or gases, these add alloying elements to the weld pool.
Gas metal arc welding is sometimes referred to by similar Welding methods such as metal inert gas (MIG) and metal active gas (MAG). (GMAW) Welding process is when an electric arc forms between a usable wire electrode and the piece of work that’s being used. This method essentially heats the metal to its melting point then cools forming a joint between the 2 metals used.
The various types of Welding processes are mostly and widely used for fabrication, construction etc. This is because the different types and their different strengths and weaknesses amalgamate to form a plethora of ways to join all different types of metals strongly and reliably. Therefore, Welding is used the most as a solid way of permanently keeping 2 pieces of metal together. For example, Welding is used to make various vehicles such as cars, aircraft and also structures like bridges, buildings, and railways lines etc. Welding is used to join pretty much anything and everything nowadays as it’s such a versatile way of doing it.
Large transport tankers for transporting goods that’s are necessities nowadays, for example, oil, water, milk etc. Tubes and pipes, chains etc. This is because these components are most likely going to go under a somewhat stressful life span, for example, the would probably get bent or dented. Fabrication of steel furniture, doors, door frames, gates. This is because these components get handled daily by people, so the welding assists the component in not giving out much earlier than anticipated and costing the owner a new one of the things that broke, just to have it break again. Manufacturing appliances, for example, refrigerators, washing machines, dish washers, microwave ovens etc. Again, these appliances are used on a very regular basis and undergo stress if the user is in a hurry to open it and swings the door about recklessly. Therefore, the welding allows the appliances life span to be increased as it is more rigid and won’t fall apart without a lot of force being applied in the process.
The requirements of the Welding for specific areas of the industry are given in following text:
Welding can be used for joining various components together, such as pipelines for crude oil, gas etc. Also, it can be used for construction of vehicles such as boats, especially tankers that can carry goods around the world, structures placed in the sea like Oil rigs, dockyards and cranes. Welding drivers usually use approximately 300-400 amps of current to power their electrode. This process commonly employs a variety of shielded metal arc welding, using a waterproof electrode. Other practices of welding include flux-cored arc and friction.
The structure for a nuclear reactor, such as the spheres, pipeline bends, the joining of pipes. These carry heavy amounts of water which require a weld to secure it safely and reliably. The welding used for manufacturing components for a nuclear reactor are usually either Gas Tungsten Arc welding and/ or Shielded Metal Arc welding with filler wires and an E 316-15 electrode with the addition of controlled heat input.
Welding can also be used effectively in the defence industry when fabricating the bodies of vehicles such as tanks and turret mounting to the body of the tanks. The types of welding that are used in the fabrication of the defence industry’s vehicles etc, are quite varied and including all the forms of Electric Arc Welding, Oxy-Acetylene, TIG and MIG.
This type of industry uses quite a limited amount of welding processes; however, brazing and soldering are widely used. This industry uses their chosen welding processes for joining leads of special/ unique transistors. The soldering in this industry is used to join electronic components like transistors, capacitors, LED’s etc. Robotic soldering fully automates this using machines, and provides a lot of accuracy when used.Electrical Industry: In this industry the main types of welding that are present are Tungsten inert gas (TIG), Metal inert gas (MIG) and Oxy-fuel welding. For MIG welding, it is the subtype to Gas metal arc welding (GMAW) and provides an electric arc that forms between a consumable wire electrode. For TIG welding, it can also be called Gas tungsten arc welding (GTAW), this process differs from MIG welding as it uses a non-consumable electrode which delivers the current directly to the welding arc. Also, the weld puddle in this process are cooled and protected by an inert gas which is commonly argon as it’s a fairly common gas and inexpensive.
This type of industry uses a welding process called thermite welding. Thermite welding or exothermic welding/ bonding (TW) is a process that employs molten metal to permanently join together 2 conductors. This type of welding is seen very often when repairing railway tracks if they are cracked or damaged. In addition, the laying of railway track requires a different welding process which is called mobile flash butt welding. Aerospace Industry: In this industry, its focused-on aircraft and spacecraft. These specialised vehicles had similar fabrication techniques to normal ship building where rivets were used as a semi-permanent joint. However, after the introduction of the jet engine, the fabrication of these vehicles was down to welding processes. The most predominant welding process within this industry is TIG, although, there types of welding processes are used as well such as MIG, Oxy-gas and a few others.
This welding process, like all others, has its advantages and disadvantages. Although it is used within many different industries and can welding almost all engineering materials, it is hampered slightly when given to weld materials with low melting points and high reactivity. However, the advantages do out-weigh the disadvantages as it is easy to operate and its margin for the thickness of materials it can weld is quite large, ranging from 1mm to 25mm. On the other hand, some alloy steels need to be preheated before welding commences. But, this isn’t a major draw-back for this welding process. This welding process is quite versatile as well because welding can be done on a flat surface, inclined, vertical and in an overhead position. Submerged Arc Welding: With this welding process (SAW), specialised materials can be welded, such as; carbon, alloy steels, copper alloys etc. Also, with this process, it is generally used for plate thicknesses above 10mm, this can be viewed as a disadvantage, however, within the various industries, there would be a variety of welding processes to choose from to get the best job done. For the advantages, its best suited for automatic welding in ship building, boilers etc. And is generally used for flat and horizontal positions but isn’t suited for cast iron.
This welding process can be used for various types of materials, such as; carbon steel, copper, aluminium, bronze etc. Also, it is best suited for sheet metal welding which is widely used throughout the various industries and can effectively weld small diameter pipes. Within this welding the process, the control over the flame is essential. It can weld plates from thicknesses up to 8mm to 10mm and employs yellow and red brass to be welded to minimize the vaporization of zinc. Knowing the correct safety steps and having the correct safety gear is essential whilst welding because the plethora of welding processes that there are have a major hazard present within using them. Having the knowledge to keep safer and having the correct equipment/ gear would reduce the risk and make it less likely for you to get hurt whilst doing welding if you are a beginner. However, if you are an experienced welder and have done it for many years and do know the various safety steps that need to be taken, it doesn’t mean that the same steps that apply to the beginners don’t apply to you. Because the hazard is always going to be there, it’s just your job to take the necessary steps the reduce the risk.