11-09-2017, 12:10 PM
Plasma Arc Welding (PAW) is an arc welding process similar to gas tungsten arc welding (GTAW). The electric arc is formed between an electrode (which is normally but not always made of sintered tungsten) and the workpiece. The key difference of GTAW is that in PAW, by placing the electrode inside the body of the torch, the plasma arc can be separated from the protective gas envelope. The plasma is then forced through a fine-bore copper nozzle that contracts the arc and plasma leaves the orifice at high speeds (approaching the speed of sound) and at a temperature of approximately 50,000 ° F (28,000 ° C) or plus.
Just as oxyfuel torches can be used for welding or cutting, so can plasma torches, which can achieve plasma arc welding or plasma cutting.
Arc plasma is the temporary state of a gas. The gas ionises after passing electric current through it and becomes an electricity conductor. In atoms of ionized state they break into electrons (-) and cations (+) and the system contains a mixture of ions, electrons and highly excited atoms. The degree of ionization may be between 1% and more than 100%, i.e.; double and triple degree of ionization. Such states exist as more electrons are drawn from their orbits.
The energy of the plasma jet and, therefore, the temperature depends on the electrical power used to create arc plasma. A typical value of the temperature obtained in a plasma jet torch may be of the order of 50,000 ° C (50,000 ° F) versus about 50000 ° F in ordinary electric arc welding. Actually all welding arcs are (partially ionized) plasmas, but the arc welding of plasma is a narrow plasma arc.
Just as oxyfuel torches can be used for welding or cutting, so can plasma torches, which can achieve plasma arc welding or plasma cutting.
Arc plasma is the temporary state of a gas. The gas ionises after passing electric current through it and becomes an electricity conductor. In atoms of ionized state they break into electrons (-) and cations (+) and the system contains a mixture of ions, electrons and highly excited atoms. The degree of ionization may be between 1% and more than 100%, i.e.; double and triple degree of ionization. Such states exist as more electrons are drawn from their orbits.
The energy of the plasma jet and, therefore, the temperature depends on the electrical power used to create arc plasma. A typical value of the temperature obtained in a plasma jet torch may be of the order of 50,000 ° C (50,000 ° F) versus about 50000 ° F in ordinary electric arc welding. Actually all welding arcs are (partially ionized) plasmas, but the arc welding of plasma is a narrow plasma arc.