Welding is a process of joining materials such as metals and plastics using heat or pressure. It is the most popularly used method today to join metals, and is used extensively in the production of automobiles, ships, trains, buildings, and bridges. Compared to soldering and brazing which introduce a soft melted substance to hold original pieces together, welding process melts the metals together to form a robust and a strong join.
Welding had been practiced since ancient days. The most popular method during this era was forge welding that cnc machine selection criteria was used by blacksmiths. This method used to weld two metals by beating them together over a hot coal.
Today, the modern technologies have allowed welders to work with much greater precision and achieve stronger welds compared to olden days. The first World War gave the impetus for the development of welding technologies, as many countries were looking for better and efficient ways of welding ships and planes for the war. From there onwards, welding technology developed into indian wood industry a modern art which could be performed manually as well as using robotic machines. In particular, it can be performed under different environmental conditions such as underwater, on-site and in workshops. In spite of these rapid advances, welding seems a highly risky and a dangerous process which can expose a welder to burns, poisonous or toxic gases and even eye damage.
Most common methods of welding practiced today are gas, arc, spot, resistance, electron beam, laser and robot welding.
Gas welding is commonly referred as Oxyacetylene where gas and oxygen are mixed together to produce a high temperature flame at the torch to melt the edges of metal that have to be welded. Hence, Oxyacetylene welding usually requires two tanks or bottles to store oxygen and the fuel acetylene. This method is one of the oldest techniques used and still practiced all over the world. This is mainly because the equipment including storage bottles are easily portable. This is extensively used for joining pipes and simple fabrication.
Arc welding uses an electrical arc between an electrode and the subject material and at the same time melting them together to create a strong bond or a weld. Arc welding is extensively used in industrial applications because it’s economical. The problem with the arc process is that sometimes welds can become brittle and weak due to oxygen and nitrogen present in the atmosphere. To overcome this problem, shielded gas such as hydrogen, argon and helium are used.
Resistance welding uses physical pressure and heat to weld materials. The heat is generated by the resistance of high electrical current passing through the materials that have to be welded. This method is popular among many industrial applications because it is easily automated and economical at high volumes of production. Due to its high initial investment cost it may not be feasible to use on low production volumes.
Spot welding is another form of resistance welding which is used to join four metal sheets. In spot welding, two electrodes are used to weld metal sheets that are clamped together while applying pressure and sending a high current through them. Spot welding can be automated and it is energy efficient, therefore it is extensively used in many industrial applications, such as automotive assemblies.
Electron beam welding process uses high velocity electron beam on the materials. When high velocity electrons bombard the materials, very high heat is produced melting the materials and creating a strong bonded joint. The electrons beam is produced by using a hot cathode emitter made out of tungsten. This method is a very precise one, and used popularly in aerospace and semiconductor industry.
Laser beam welding process join multiple pieces of metal using a concentrated heat source. This method is not only precise and but also efficient because of very little heat loss from the specific area. Also, the laser is able to penetrate heat deep into the metals welded. Laser beam welding is used in automated automotive assembly plants.
