In electric welding processes, an arc is produced between an electrode and the work piece (base metal). The arc is formed by passing a current between the electrode and the workpiece across the gap. The current melts the base metal and the electrode (if the electrode is a consumable type), creating a molten pool. On solidifying, the weld is formal.
Read more →CARBON ARC WELDING (CAW) a. General. Carbon arc welding is a process in which the joining of metals is produced by heating with an arc between a carbon electrode and the work. No shielding is used. Pressure and/or filler metal may or may not be used. b. Carbon arc welding Equipment. (1) Electrodes. Carbon electrodes range in size from 1/8
Read more →a. General. Resistance welding is a group of welding processes in which the joining of metals is produced by the heat obtained from resistance of the work to the electric current, in a circuit of which the work is a part, and by the application of pressure. The three factors involved in making a resistance weld are the amount of
Read more →a. Arc Welding Electrodes. When molten metal is exposed to air, it absorbs oxygen and nitrogen, and becomes brittle or is otherwise adversely affected. A slag cover is needed to protect molten or solidifying weld metal from the atmosphere. This cover can be obtained from the electrode coating, which protects the metal from damage, stabilizes the arc, and improves the
Read more →Arc Welding Equipment a. Arc Welding Equipment : Cables. Two welding cables of sufficient current carrying capacity with heavy, tough, resilient rubber jackets are required. One of the cables should be composed of fine copper strands to permit as much flexibility as the size of the cable will allow. One end of the less flexible cable is attached to the
Read more →a. Starting to Weld. (1) Press the inch button and allow enough wire electrode to emerge from the nozzle until 1/2 in. (13 mm) protrudes beyond the end of the nozzle. With the main line switch “ON” and the argon gas and power sources adjusted properly, the operator may begin to weld.(2) When welding in the open air, a protective
Read more →MIG Welding Equipment | Gas Metal Arc Welding (GMAW) a. MIG Welding Equipment, Gas Metal Arc Welding (GMAW). GMAW is most commonly referred to as “MIG” welding, and the following text will use “MIG” or “MIG welding” when referring to GMAW. MIG welding is a process in which a consumable, bare wire electrode is fed into a weld at a
Read more →Gas Tungsten Arc Welding (GTAW) : TIG Welding Equipment a. Gas Tungsten Arc Welding. In tungsten inert gas (TIG) welding, (also known as GTAW), an arc is struck between a virtually non-consumable tungsten electrode and the workpiece. The heat of the arc causes the edges of the work to melt and flow together. Filler rod is often required to fill
Read more →a. Most of the alternating current arc welding machines in use are of the single operator, static transformer type (fig. 5-19). For manual operation in industrial applications, machines having 200, 300, and 400 ampere ratings are the sizes in general use. Machines with 150 ampere ratings are sometimes used in light industrial, garage and job shop welding. b. The transformers
Read more →a. The direct current welding machine has a heavy duty direct current generator (fig. 5-17). The generators are made in six standardized ratings for general purposes as described below: (1) The machines rated 150 and 200 amperes, 30 volts, are used for light shielded metal-arc welding and for gas metal-arc welding. They are also used for general purpose job shop
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