Since the industrial revolution, the technological advancements of mankind have been moving at an unprecedentedly brisk pace. The different human industries likewise have manifested great innovations. With the introduction, for example, of steel as a construction material, the different fabrication methods and techniques have been significantly developed, and because of the limited natural sources of mineral ores for the steel building, the process of recycling and joining metals have becomes inevitable. At the onset, the most commonly-used method of joining steel together was either by bolts or rivets. However, due to the intensiveness of the riveting and bolting process, other methods of joining steel had to be developed, and for this reason, the process of welding steel joints was afterward introduced.
Welded joints, especially, in steel fabrication, are found to be far stronger than riveted or bolted joints, for welded metals are bonded together by means of fusion. In fusion, the base metal or workpieces are heated, melted, and joined together at the molecular level. Moreover, in its earliest form, welding was done by hammering two pieces of red-hot metals together until they fused. This process is now called “forge welding.”
Another early form of welding is the Oxy-fuel welding/cutting. Otherwise known as “oxyacetylene welding” for its use of Oxygen as oxidant and acetylene as fuel, oxy-fuel welding produces high-temperature flame to heat and melt the base metal or workpiece to create a molten pool where filler of similar metal is added to form a molecular bond. Oxy-fuel cutting is somewhat identical to the oxy-fuel welding, but instead of melting the workpiece to create a bond, oxy-fuel cutting uses a different type of torch that produces a flame that could cut through the metal.
The same oxyacetylene welding equipment is employed in brazing and/or soldering, albeit using solder wire instead of filler. Arc welding, on the other hand, uses a similar procedure to oxy-fuel but employs electrical arc rather than flame, and thus it achieves higher welding speed.
Arc welding is the most common metal-welding technology today. Arc welding uses electrical arc (concentrated near the tip of the electrode) to heat and melt the base metals or workpieces that are to be welded along with the filler material that creates a bond at the joints. There are various types of arc welding, and some of the most common arc welding processes are:
Different Types & Processes of Welding
1) Shielded Metal Arc Welding (SMAW)
Shielded Metal Arc Welding (SMAW)—SMAW, also commonly known as “Stick” welding due to its use of rods or stick electrode, is the predominantly used type of arc welding. The consumable electrode serves as the filler material and is coated with flux. The flux coating produces a shielding gas that protects the molten pool from atmospheric effects. The same flux is also deposited on top of the molten pool and forms a material called “slag” to protect the pool as it cools.
2) Flux-Cored Arc Welding (FCAW)
Flux-Cored Arc Welding (FCAW)—FCAW is very similar to SMAW except that FCAW uses a continuous electrode. But instead of being coated with flux material, the consumable FCAW electrode uses a fine metal tube filled with flux.
3) Gas Metal Arc Welding (GMAW)
Gas Metal Arc Welding (GMAW)—Like FCAW, GMAW or more commonly MIG (Metal Inert Gas) welding uses a continuously-fed consumable wire electrode that also acts as filler material to the weld. However, in MIG welding, the wire electrode is without flux and must rely on an external shielding gas.
4) Gas Tungsten Arc Welding (GTAW)
Gas Tungsten Arc Welding (GTAW)—Otherwise known as TIG (Tungsten Inert Gas) welding, the GTAW welding is unlike most arc welding processes that utilize a consumable electrode that also acts as filler material. Contrariwise, TIG welding uses a tungsten electrode to create an electrical arc and uses a separate, manually-introduced filler wire. TIG welding also uses an external shielding gas similar to that of GMAW welding.
5) Submerged Arc Welding (SAW)
Submerged Arc Welding (SAW)—SAW process differs from most arc welding processes for, in the case of SAW, the electrical arc is submerged under a layer of flux. The flux covers the welding from atmospheric contaminants and prevents spatter or sparks from flying. The flux also shields the operator from the intense UV (ultra-violet) light that the arc creates. Moreover, the molten flux serves as an electrical conductor between the consumable, continuous electrode and the workpiece. SAW is usually available in automatic or mechanical form; however, there are portable, manually operated models with pressurized or gravity-fed flux delivery system.
Types of Welding Jobs
It is basically self-evident that no one can perform perfect welding without having welding skill. Welding skill is the knowledge that can only be acquired through practice. At the onset of the development of the different welding processes, welders generally gained their welding skills through apprenticeship. At present, however, welding courses are already offered to train those who would like to become welders. After learning the basic techniques and principles, the prospective welders must further learn other skills related to welding like the knowledge of how to read technical drawing plans. Moreover, the ideal welders should be proficient in two or more welding types.
Since most modern structures and means of transportation that we use today are made of steel, there is definitely a huge demand for welding skills. Hence, welders will surely never run out of job, and job opportunities for welders are mostly needed in various industries. Here are some in-demand jobs for welders:
1) Pipe Fitter
Pipefitters are generally responsible for pipe layout and installation of all piping systems found in buildings and other constructions, HVAC (heating, ventilation, air conditioning) fabrication and plumbing. Due to their work responsibility, pipe fitters need to acquire additional skills such as the proficiency in reading blueprints and drawing aside from the basic knowledge of laying and joining pipes together.
2) Sheet Metal Worker
The fabrication of items such as those of air conditioning and heating ducts as well as rain gutters require some adroitness on the part of a sheet metal worker. Hence, aside from welding, welders need to have basic knowledge of oxyacetylene welding and soldering process for thin sheets of metal do not need very high-temperature heating process. Sheet metal workers should also be learned in fabricating parts of cars, airplanes, and boats.
3) Fabrication Welder
The fabrication welder is required to cut and weld metals to fabricate parts of machines. Moreover, they are required to follow engineering drawings and specifications. There are two categories of fabrication welders: light and heavy. Light fabrication welders usually work in fabrication companies of car chassis and body as well as in fabrication companies of vehicles, metal chairs or table, water tanks, and reservoir. Fabrication of bridges and shipbuilding falls under the category of heavy fabrication welder. Heavy fabrication welders usually work with heavy and thick metals that need deep welding joints.
4) Welding Inspectors
A certified welding inspector needs to be a very experienced welder as he needs to examine and determine if the welding satisfactorily meets the specified requirements or specifications. To become a welding inspector, one is required to have significant experience in arc welding, gas welding, as well as in pipe welding. Moreover, to be a welding inspector, one needs to be adept at reading blueprints and other fabrication drawings. Furthermore, he has must have necessary skills in drafting. Lastly, the welding inspector is required to have a firm foundation in physics and mathematics.
Understanding Welding Job Categories
Due to the vastness of the scope covered by welding that includes various welding procedures, types, tools and machineries, welding jobs themselves have three general categories, namely, cutters, brazers and solderers, and welders and welding machine operators.
1) Welders and Welding Machine Operators
As mentioned earlier, welders need to know at least two types of welding processes, especially, in the field of arc welding. In manual welding operation, the welder needs to know how to set up the welding machine and must have the knowledge about equipment, materials, and garments that are required for a specific welding job. The same is true of welding machine operators. However, welding machine operators must also be well-versed with various techniques and welding procedures. They should also be adept in using welding machines. It is important to note here that welding machine operation is mostly employed in large-scale production and fabrication using semi-automated welding processes.
Similar to welding, cutters must have the know-how on using manual and machine cutters that use plasma, oxy-fuel or electric arc to trim or cut a workpiece to its precise dimension and shape. They must also know how to use these tools in cutting and chopping fixed-metal structures such as steel bridges into smaller pieces for recycling or scrapping. On the other hand, cutting-machine operators are employed to dismantle movable large metal structures (ships, airplanes, cars, and locomotives) into their smaller components.
3) Solderers and Brazers
Similar to the welder in various respects, solderers, and brazers don’t use very high temperatures and don’t need to melt the workpieces that are being joined. They instead heat the workpieces together with the solder material to join the workpiece together. Moreover, while solderers and brazers share common work procedures and materials, brazers only engage in melting the soldering material. Lastly, the brazing process requires the workpieces (such as pipes) that will be joined are closely fitted so that the melted soldering material can flow through the gaps between the workpieces via capillary action.