The welding torch fever heat source main reasons: 1 arc heat: welding arc radiation temperature, and the temperature of molten pool thermal radiation cause the welding torch to heat up, the greater the greater the heat of the welding current; The cable resistance heat: the resistance of heat generated by the current through the cable, the same with the current proportional to the. Torch cooling method: 1 air-cooled welding torch: by welding torch heat capacity heat; Water-cooled torches: rely on the heat of cooling water through the torch internal plumbing. Welding torch duty cycle: Refers to the specific current cycle of 10 minutes, welding torch can continue to work on the instructions of the welding torch are marked Do not use more than the duty cycle. When exceeded, will cause the welding torch damage. Maximum current of the welding torch through: Usually the maximum current models of the welding torch welding torch that can be adopted, such as Panasonic's YT-208 welding gun, the maximum current is 208A, welding current use shall not exceed the the welding torch maximum allowable current value. In addition, with CO2 welding torch, welding, CO2 gas cooling, the the Ar cooling effect is far below the CO2 it is also TIG gun easy to heat.