Research Of The Welding Process Of Consumable Double Electrode With A Single Arc GMAW

It is an important way to enhance welding productivity by making use of high efficient welding method. A higher welding speed needs a higher deposition rate of filler metal. However, in traditional GMAW the increase of the current through the filler wire with the increase of the wire feed speed will cause an increase of the current through the work piece simultaneously. The undue current through the work piece would bring extra heat input to the work piece, which may result in welding deficiency. DE-GMAW is different, which could offer a high efficient and high property welding process. The heat input to the work piece could be controlled and then a more reasonable heat distribution could be obtained by DE-GMAW. Now a new welding method relevant to DE-GMAW was developed, which is named consumable double electrode with a single arc gas metal arc welding(consumable DESA-GMAW).In consumable DESA-GMAW, the stability of the welding system gets improved and the deposition rate and deposition coefficient is enhanced.The electrical signals of the welding system and the high speed photography were acquired synchronously in the welding process to reflect the arc behavior and metal transfer process precisely. The cross section photos of the weld bead were also used to study the welding process of consumable DESA-GMAW. There are two consumable electrodes but only one arc in the consumable DESA-GMAW system. The main wire is connected with the anode of the main welding source and the anode of the slave welding source, the bypass wire is connected with the cathode of the slave welding source, and the work piece is connected with the cathode of the main welding source. The total current provided by the two welding sources flows through the main wire. The bypass wire is used to decouple current so that a part of the current through the main wire could be divided into two parts after the current flowing through the arc: one part through the work piece and the other part through the bypass wire. This would decrease the heat input to the work piece and the heat could be used to melt the bypass wire, which can bring about a high deposition coefficient of the welding system. The welding process of consumable DE-GMAW is very stable. The metal transfer mode of the main wire could be one droplet per pulse, several droplets per pulse or one droplet several pulses. The bypass wire keeps short circuit condition with the work piece and it could be fed into the welding pool smoothly.The influences of the preset value of the main power source, the preset voltage of the slave power source, the wire feed speed of the main wire, the wire feed speed of the bypass wire on the current through the main wire, the work piece and the bypass wire, the metal transfer mode of the main wire and the bypass wire and the deposition coefficient of the main wire, the bypass wire and the welding system and the weld bead shape were studied. The change of the preset value of the main power source and the preset voltage of the slave power source could be used to adjust the ratio of the current through the work piece and the current through the bypass wire, which could provide a precise control of the heat input to the work piece along with a higher deposition rate.