Preparation Of Magnesium Alloys Wire With Flux And Its Automatic TIG Welding

This study carried out the selection of the active flux, the preparation of welding,the coating method of the flux on the wire, contradistinction of the welding process andeffect between the TIG welding with conventional wire and the TIG welding with thewire with active flux and so on, which wants to develop a new kind of wire with fluxand the welding specifications of automatic TIG welding wire. The results showed:Using distilled water instead of the organic solution can make the flux easier tofully dissolve, which eliminated the stringent requirements of the degree of dryness andmilled of the flux when using other solution. Making the wire go through the aqueoussolution of the active flux, and then dried, the close contact powdered deposition of theactive flux would be deposited on the surface. With distilled water as the solvent canalso get higher solubility of the active flux. The surface area increased though thedesigning cross-sectional shape of bare wire, the recessed region can adsorb moresolution with the help of the surface tension, which made it adsorb more active flux.The active flux can hardly be scraped when the wire went through automatic wire feeder,because it can be avoided contact with the channel wall. The actual effect of automaticTIG welding when using the active wire showed that the surface quality of the weld, theweld penetration, macroscopic defects of welding, welding Structure, and tensilemechanical properties can hardly be influenced by the drying extent of the active flux.The penetration of the active flux increased with the welding current increasingwhen using AZ61and AZ61wire, but when achieving the same smooth and beautifulpenetration effect, the required welding current of the active wire was30A less, in thisstudy, penetrated3mmAZ31plates, using ordinary wire needs180A, while the activewire only needs150A. Increase welding current can help penetrating and get morestable and consistent mechanical properties. Using ordinary AZ61wire, when thewelding current increased from135A to165A, the tensile strength of welded jointsincreased from163.40MPa to225.53MPa, the extension rate increased from4.3%to11.7%, while using active wire, the tensile strength and the extension rate increasedfrom190MPa to250.38MPa, and5.5%to17.5%, respectively, when the weldingcurrent increased from105A to135A. When they were completely penetrated, usingordinary wire, the tensile strength and the extension rate was224.69MPa,13.9%, respectively, while the value of the active wire was242.07MPa and16.4%. Thescanning results of tensile fracture of welded joints of TIG welding with active wireshowed that the fracture has holes when the current was120A and135A, while thecurrent increased up to150A and165A, the fracture is mainly composed of dimple andtear edges and has no obvious defects, which confirmed the high welding currents canhelp to get a good metallurgical quality of the weld area cast alloys. After using theactive wire, welding arc expanded anomalously, which may be caused when halogenexchange to anion, releasing exotherm and extended around the arc. The element activeagents was not detected in the weld of the active wire, which may be the active flux wasused as an active welding wire in the welding process.The wire with five different single-component active flux (KCl, NaCl, LiCl, CaCl2and NaF) was studied. The welding penetration and D/W of LiCl and CaCl2increased,unchanged when NaF wire was investigated, while decreased with NaCl and KCl wire.Unfortunately, LiCl and CaCl2could not refine the microstructure of weld zone.Compared with the normal wire weld, weld joints with CaCl2had a higher FZmicrohardness and a lower HAZ hardness, while had a evenly distributed hardness withLiCl. Compare the fracture location and tensile strength of weld joint, weld with LiClwire was better than CaCl2flux. Using LiCl, CaCl2as flux wire, making the welding arcand the weld penetration of the active wire TIG welding increased at the same time.