Metalworking involves the intricate process of casting, cutting, forming, and joining metals to create components, assemblies, and large structures. Metalworkers use a variety of tools, skills, and processes to create a wide range of objects and infrastructure, such as bridges, buildings, engine parts, jewelry, and even large shipping vessels. Metalworking has existed for thousands of years as an exact science, hobby, art, and trade. In fact, metalworking evolved from the act of smelting ores to a full-blown industry. Metalworkers report to a machine shop equipped with hundreds of tools capable of creating an array of items.
Types of Metal
The art of metalworking has existed for thousands of years, insomuch that the ancients knew of seven metals that would work to form objects and structures for utilitarian and aesthetic value. These metals include gold, silver, mercury, copper, tin, lead, and iron. Modern metalworking and fabrication processes use steel shapes and forms, such as carbon steel bars, sheets, strips, plates, wire, wire products, and tin plates. In addition, the metalworking industry uses stainless steel, alloy steel, iron, and aluminum to create a variety of castings, forms, cuts, and joints.
Metalworkers use a variety of tools to cut, shape, bore, and thread numerous types of metals. In addition, metalworkers may use manual or electrically powered tools to perform different tasks. Hand operated tools include shears, files, hammers, and hacksaws. Electrically powered tools include drills, taps, band saws, grinders, and dies. Metalworkers use hacksaws, tools designed with multiple fine teeth, to make precise cuts in metal. Hacksaws cut through almost any type of metal, including copper, aluminum, brass, hardened steel, and cast iron. Metalworkers employ hammers to straighten or create indentations in metal.
Files serve to smooth out rough edges after cutting the main pieces of metal. In addition, files add shape to an existing work piece. Metalworkers use grinders to smooth out very large edges in a metal work piece, oftentimes on a table mount. Grinders feature abrasive wheels that rapidly turn to sand, polish, cut, and sharpen metal. Metalworkers may also use mechanically powered band saws to quickly cut large pieces of metal, usually on a bench mount. Drills serve to bore holes of various diameters into an existing work piece. Taps and dies create a threaded surface on the inside and outside of a metal work piece.
Metalworkers employ casting processes when they want to create an object from liquid metal. They achieve this by pouring the liquefied metal into a pre-shaped, hollow mold and then giving it time to cool and solidify prior to removal. Metalworkers refer to the solidified object as a casting, which gets ejected from the mold to complete the process. Metalworkers employ casting when they want to create complex shapes unattainable by other methods. Metalworkers typically use casting for sculpture, especially when using precious metals and bronze to create jewelry, weapons, and tools. Metalworkers define casting in two different categories, including expendable and non-expendable processes.
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Metalworkers employ forming processes in order to modify metal, and existing workpieces without removing any material. Metalworkers use a heated mechanical system to deform metal or work pieces into a desirable shape, especially with bulk forming. Metalworkers use mechanical systems that apply force to metal and work pieces at room temperature to create a desirable shape, a process referred to as sheet forming. Modern industrial processes may involve heating dies and other components when forming metal.
Metalworkers employ cutting processes when they want to create geometric shapes in metal and existing work pieces. Cutting may require numerous kinds of tools that will create a finished product that meets the metalworker's specifications. Cutting may involve various technologies that produce the desired finished product, including machining, burning, drilling, turning, milling, grinding, sawing, welding, plasma, oxy-fuel burning, laser, water jet, and electric discharge.
Machining, also known as milling, involves the process of creating complex shapes of metal and other raw materials to form a final product. Metalworkers typically use milling machines, or electrically powered devices that rotates on a spindle axis, to create complex three-dimensional objects. Milling machines perform a variety of complex operations, such as threading, rabbeting, planing, drilling, and routing. Metalworkers can mill a wide range of metals, including aluminum and stainless steel.
Turning involves the intricate process of cutting metals to produce cylindrical surfaces with a single-pointed tool. Metalworkers use lathes to rotate the work piece on a spindle that spins axially and radially. Lathes can create round ended objects, such as camshafts, bearing mounts, baseball bats, table legs, bowls, and candlestick holders. Metalworkers use a variety of softer metals while turning. Other cutting methods include threading, grinding, and filing. Threading involves cutting threads of metal with a tape or die. Grinding involves cutting metal with an abrasive wheel, usually to smooth out rough edges. Filing combines grinding, and saw-tooth cutting to flatten out metal surfaces.
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Metalworkers also specialize in joining metal together after shaping it through a series of fabrication processes, such as welding, soldering, brazing, and riveting. Welding involves the act of enjoining metals together by inducing coalescence. Metalworkers cause coalescence by melting the existing work pieces and then adding filler to form molten material. The molten material eventually cools to form a strong joint. Welders employ a gas flame, electric arc, lasers, friction, ultrasound, and electron beams to join work pieces together.
Brazing involves enjoining work pieces by drawing liquefied filler metal into a capillary of multiple work pieces. As the filler metal enters the capillary, it causes a metallurgical reaction with the work pieces and solidifies to form a strong joint. Metalworkers do not melt the work piece when brazing, and it produces minimal thermal stresses compared with welding. Metalworkers employ several brazing techniques, including resistance brazing, furnace brazing, inductive brazing, flame brazing, and diffusion brazing.
Soldering involves the process of enjoining metal at temperatures below 842 degrees Fahrenheit. Soldering functions in the same way as brazing, except it occurs at a lower temperature; however, the minimal metallurgical reaction that occurs while soldering results in a weaker joint. Riveting, an ancient metalworking joining process, involves the assembling of two work pieces with an unthreaded bolt. The metalworker drills or punches holes through two pieces of metal and then aligns before joining them together. In order to remove a rivet, a metalworker must use a hammer to drive it out.
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Metalworkers may also employ nontraditional metalworking processes before or after the primary construction of work pieces. For instance, metalworkers may apply a heat source to two enjoined pieces of metal to alter its strength, toughness, hardness, and ductility. Metalworkers identify these heat treatment processes as quenching, tempering, annealing, and precipitation strengthening. Plating involves treating the surface layer of metal by bonding two work pieces with another metal, such as chromium, zinc, gold, and silver. Plating reduces corrosion; therefore, improving the product's overall aesthetic appeal. Metalworkers also apply thermal spraying techniques to promote proper finishing to the product.
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