| A experimental platform with data acquisition and high-speed photography was established.The arc shape and Metal transfer characteristics of the twin-wire GMAW was studied by experimental.In CO2twin-wire welding, When the currents pass through the double wires are non-pulsed, the electromagnetic interference between the arcs is serious, almost no application in the actual production. When the pulse and non-pulsed current cross combinations in the double wires, the two wires together with small current, low voltage, the droplet is short-circuiting transfer to weld pool and the welding process is more stable. When the currents pass through the two wires are pulsed, should minimize the arcs length. If the arc length is too long, the arcs move here and there around a molten pool, and even intertwine together by the electromagnetic blow, and are not work independently. The droplet transition is in the form of large particles and welding spatter is very serious, the welding process instability.In MIG/MAG twin-wire welding, when the pulse and non-pulsed current cross combinations in the two wires. To reduce electromagnetic interference, keep the current of non-pulsed with small current and low voltage, the droplet is short-circuiting transfer to weld pool under the role of non-pulse current, the other wire with spray transfer, one pulse one drop, now the welding process is more stable. When the currents pass through the two wires are pulsed; The peak of the pulse is fixed, the output energy is controlled by pulse duration. If the time of pulse duration is too long, the form of metal transfer is one pulse more drop; if too short, the form of metal transfer is more pulse one drop, they all aren’t conducive to the seam formation. The best form of metal transfer is one pulse one drop. So the time of pulse duration can be controlled to keep one pulse one drop. In MAG twin-wire welding, the CO2content must be limited below30%, otherwise the metal transfer can’t achieve a pulse a drop. |
PDF Full Text Request