Welding & Cutting ǀ Oxyacetylene (Oxy-Fuel) ǀ Process Tools & Types
Welding is a technique that involves the joining together of two or more metallic pieces into one single piece of metal through heating, whilst the cutting process involves the separation of metal through heating. The metallic piece turns to a molten state after intense heating. There are several types of welding and cutting processes, such as gas welding, arc welding, forge welding, resistance welding, spot welding, oxyacetylene welding, electron-beam welding, friction welding, cold welding, laser welding, etc. In terms of the weldability of metals, carbon and low alloy steel are the materials used most widely in welding. Besides, aluminium, copper, nickel, and refractory metals such as zirconium, niobium, and tungsten can be welded by using the right welding process.
Arc welding is a process of welding that uses an electric arc to produce strong heat to melt metal. The arc is formed between the metal and an electrode which carries current, melts, and transfers the filler metal to the joint. The temperature the arc produces melts the metal and the electrode, which turns the metal into a molten state. There are a few types of arc welding. The common types are such as shielded metal arc welding, gas metal arc welding, gas tungsten arc welding, and plasma arc welding.
Forge welding is initially used to join small pieces of iron into larger pieces. The iron is shaped before it is joined together and is heated to a temperature in a forge. It is then hammered to produce a forged weld. The process keeps on repeating until the forged iron reaches the strength desired.
Spot, seam, and projection welding lie in the category of resistance welding. The process usually uses the electrical resistance of the joint to produce heat. Welding is achieved using a low voltage and high current power source with two electrodes on both sides applying force to the joint. In spot welding, sheet metals overlap and are spot welded at regular intervals where the joint strength is depending on the size and number of welds. Whereas seam welding uses electric current to pulse into the joint, forming a continuous seam. On the other hand, projection welding is the formation of a projection weld by using a resistance machine to press on the parts to be welded to form a protuberance that melts during welding.
The electron-beam welding process is performed by having a dense stream of high-velocity electrons to produce energy which is transferred as heat. The metal piece is placed in a chamber with a beam focusing device where the beam leaves a hole through the joint upon intense heat.
Friction welding brings two metal pieces together by having the material become plastic with frictional heat developed at the linking. With plastic deformation, a strong joint is formed. As the temperature rises at the joint, overheating is prevented as the friction coefficient is decreased.
Cold welding joins the metal pieces together by pressure instead of using heat. The surfaces of the metal pieces are prepared and pressed together when pressure is applied to deform the joint. The intensity of pressure applied to the metal piece depends on the type of material and pressure can be applied using pneumatic tooling or by punch presses.
Laser welding is a process using a laser source to emit light energy to fuse the metal pieces. This method is not widely used for welding as the availability of lasers for most welding purposes is limited and there is difficulty in controlling the speed and thickness that can be welded as it is controlled by the thermal conductivity of the metals.
Gas welding, sometimes also known as oxy-fuel welding, is another technique to weld. This technique is slow and easier to control when compared to arc welding. The metal pieces are combined by a heat source produced as a result of the combustion of fuel gas, such as acetylene, methylacetylene (MAPP), or hydrogen gas. The gas is stored in compressed gas cylinders and the type of gases used can be oxygen, acetylene, hydrogen, or propane.
Oxyacetylene welding has many uses such as hardening, tempering, heating, brazing, welding, and cutting. This is because this approach has precise control over the heat input and the temperature flame. Moreover, it has advantages compared to other fuels, such as heating metals quickly, has good control of puddle viscosity, and has multi-functions at a low cost. Nevertheless, oxyacetylene is hazardous as it can cause fire explosions, burns, asphyxiation, or gas leaks. Therefore, safety precautions should be ensured during the process of oxyacetylene.
Oxyacetylene welding equipment consists of two gas cylinders, which are an oxygen cylinder and an acetylene cylinder with hoses attached to the cylinders. The equipment also has pressure regulators, flame arrestors, and a torch. It is a lightweight and portable equipment that does not require any electrical power source. In the process, acetylene combines with oxygen to ignite a flame. Acetylene is a man-made hydrocarbon compound. It is formed from two carbon atoms and two hydrogen atoms (C2H2). Whereas oxygen is made by fractional distillation of liquid air where the atmospheric air is cooled and compressed repeatedly to liquid air and separated. In the welding process, heat is formed by burning acetylene in oxygen to produce a controlled flame. Metal is later added to the joint in a cold filler wire form.
Oxyacetylene is used more for cutting than for welding. It has benefits such as portable, can cut in all directions, easy to use, and cost-effective. An oxyacetylene cutting equipment can be converted from oxyacetylene welding equipment, by replacing the welding nozzle with a cutting tip. The cutting tip is attached on top of the flame torch. The cutting process requires higher oxygen consumption and rapid cylinder depletion than in the welding process. When oxygen and acetylene are mixed in the right proportions, a hot flame is produced and the temperature is high enough to melt and cut the metal piece. The flame can be adjusted as the ratio of the oxygen to acetylene is changed.
Where to Get a Welding & Cutting Products and Systems Providerin Malaysia
Aathaworld Sdn Bhd can supply, fabricate and weld many types of metal, steel, copper, aluminium, bronze, or other custom made welding and fabrication for indoor and outdoor, consumer goods, industrial, construction, light and heavy industrial usage, plant and factories, equipment and machineries, decorative façade, customizable specification to make sure you have the best quality welding and fabrication in Malaysia to fit your requirement. As a custom made welding engineering products, equipment, refill supplies and service provider in Malaysia, we are able to provide customize specification, gear welding, gearbox welding, aluminium, sheet metal, precision metal welding, iron, stainless steel, mild steel, piping welding, bolt and nut welding, flanges welding, steel plate rolling, welding, cutting, polishing, turning, boring, drilling, fabrication and welded materials supply for your requirement or projects in KL Kuala Lumpur, Selangor, Klang Valley, JB Johor Bahru, Penang, Malacca (Melaka), Seremban Negeri Sembilan, Perak, Pahang, Kuantan, Kelantan, Terengganu, Perlis, Alor Setar Kedah, as well as Sabah and Sarawak for East Malaysia; in some circumstances, we are also able to be your supplier and welding contractor for other countries in Southeast Asia (SEA) such as Singapore, Myanmar (Burma), Cambodia, Vietnam, Laos, Thailand, Indonesia, Philippines, Brunei, Bangladesh as well as China, Taiwan, Hong Kong, Australia and New Zealand.
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