Study On Aluminium Alloy Pulsed Vptig Welding Power Supply And Welding Process

With small density, high intension and anti-corrosive ability, aluminum and its alloy have been widely used in many domains such as aeronautics industry, space industry, nuclear industry as well as military industry, etc. The pulsed VPTIG as a new welding method developing in recent yeas has a big advantage on other welding methods, and will be extensively applied in future . The welding arc force modulated by low frequency of this welding method is able to wash out welding pool to decrease core , control welding crystal , and control welding line on the basis of weakly tungsten burned and stable welding arc. The high frequency welding method is able to decrease the arc energy density on the basis of keeping its welding arc force, decrease the arc's diameter, welding line and the soften degree of the hot influence area, and increase welding line intension and extensibility. Therefore, pulsed VPTIG(PVPTIG) is a very important welding method for welding aluminum and its alloys in aviation and aerospace realm.In this paper a pulsed VPTIG(PVPTIG)welding system used for welding aluminum alloys is established including welding power supply, welding stepped workbench, wire feeder . The welding power supply which is a double inverter controlled by microchip MSP430F449 works stably, its output current's positive and negative value and time can be adjusted independently and respectively, and is easily to output the variable polarity current modulated by high and low frequency by using software. The wire feeder works stably, and has the anti-direction pulling function to avoid wire adhesive to work piece, which improves welding process stability. The welding workbench runs credibly and stably, the speed regulates conveniently, and has the route of travel limit, positive and negative turn etc. In the welding process, welding power supply, wire feeder and welding workbench can be controlled by software to complete sequence control, and achieve automated control primarily, which create a credible, stable and practical welding system platform for welding process research.In this paper, the welding arc's electric characteristic, thermal characteristics and mechanic characteristic are analyzed and concluded by using high speed video ,memory oscillograph etc. The analysis of the VPTIG arc's electrical and thermal characteristics provides abundant theory sustain for aluminum alloys VPTIG process. When VPTIG welding, decreasing DCEP time and increasing DCEP current value can decrease the tungsten burned furthest on the basis of excellent oxid eliminated to improve welding...