Repository Home. Online Testing. Rescue Contests. Archived Exams. Links Library. What is a Hot Work Permit The Hot Work Permit system is intended to assure that the individuals involved in construction, renovation, repairs and maintenance of University facilities are aware of the hazards associated with hot work and welding and that they implement control measures to help mitigate them.
Contact Us. Find Us On Facebook. Responder Emergency Med. The following are types of welding processes according to the method of heat generated:. MIG welding holds for metal inert gas welding. In this types of welding, a thin wire works as the electrode which is fed from a spool attached on a gun through a flexible tube and comes out of the nozzle on the welding gun or torch.
The wire is fed continuously when the trigger is pulled on the welding gun. It is also identified as hand-operated metal arc welding, flux shielded arc welding, or stick welding.
In this type of welding process in which the arc is struck between the metal rod or electrode flux coated and the workpiece, the surface of both the rod and the workpiece melting to create a weld pool.
The simultaneous melting of the flux coating on the rod will produce gas and slag, which shields the weld joint from the environment.
Shielded metal arc welding is a various process ideal for joining ferrous and non-ferrous materials with the thickness of the material at all positions. This welding process is likewise called as gas welding. TIG welding employs a tungsten electrode because tungsten has a high melting point.
Non-consumable electrodes do not mean that it does not last forever and it means that it does not melt and becomes part of the weld. Plasma arc welding PAW is an arc welding process utilizing heat generated by a compressed arc between a tungsten non-consumable electrode and workpiece transferred arc process or water-cooled constricting nozzle non-transferred arc process.
The plasma is a gaseous mix-up of positive ions, electrons, and neutral gas molecules. The transferred arc process creates plasma jets of high energy density and can be used for high-speed welding and cutting ceramics, copper alloys, steels, aluminum, nickel alloys, and titanium alloys. Electron beam welding is a welding process that applies the heat created by a beam of high energy electrons.
The electrons hit the workpiece and their kinetic energy is converted into thermal energy heating the metal so that the edges of the workpiece can be connected and a weld is formed after freezing. EBM is also a liquid state welding process. In which, the metal-to-metal joint is made in a liquid or molten state. It is also described as a welding process because it accepts electrons kinetic energy to join two metal workpieces.
Laser Beam Welding LBW is a welding process, in which heat is formed by a high energy laser beam targeted on the workpiece. The laser beam heats and melts the ends of the workpiece, making a joint. In laser welding LBM the joint is formed as a sequence of overlapped spot welds or as a continuous weld. Laser welding is employed in the electronics, communications, and aerospace industries, to manufacture medical and scientific equipment, incorporating small components. Gas welding is performed by melting the sides or surfaces to be connected by gas flame and providing the molten metal to flow together, thus creating a solid continuous joint upon cooling.
Oxygen-acetylene mixtures are used to a very greater extent than others and hold a prominent position in the welding industry. This type of welding is almost similar to MIG welding. In fact, MIG welders can often perform flux-cored arc welding. In this welding, the wire has a core of flux that forms a gas shield around the weld.
This reduces the demand for external gas supply. FCAW is better suited for rough, heavy metals because it is a high heat welding process.
It is usually used for heavy equipment repair for this purpose. It is a process that does not produce too much waste. Because there is no need for external gas, it also costs less. Atomic hydrogen welding is an extremely high-temperature form of welding known as arc-atomic welding. This type of welding requires using hydrogen gas to shield two electrodes formed of tungsten. It can reach temperatures above an acetylene torch and it can be done with or without filler metal.
It is an advanced welding process that is used to connect the thin ends of two metal pieces vertically together. Instead of the weld being used to the outside of a joint, it will take place between the ends of the two pieces. A copper electrode wire is fed through a metal guide tube that will act as a filler metal. When power is added, the arc is produced, and a weld is started below the seam and moved up slowly, creating a weld in place of the seam.
The most obvious type to perform is the flat position, sometimes called the down hand position. This involves welding at the top of the joint. In this case, the molten metal is pulled downward at the joint. The result is a quicker and easier weld. In 1G and 1F, number 1 relates to the flat position, while letter G is for a groove weld and letter F is for a fillet weld. This is a more difficult position than the flat position and requires more skill from the welding operator to correct it.
For the face of the weld, it must lie about in a vertical plane. In this position, the torch is normally kept at an angle of 45 degrees. In this position, both the piece and the weld lie vertically or nearly vertically. When welding is done vertically, the force of gravity pushes the molten metal downward and therefore has a tendency to stack. To counteract this, you can use an upward or downward vertical position.
To check it in an upward vertical position, point the flame upward, placing it at an angle of 45 degrees to the piece.
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