What are the advantages and disadvantages of argon arc welding?

What is argon arc welding? What materials can be welded with argon arc welding? What are the advantages and disadvantages of argon arc welding?
Answer: Argon arc welding: It is the abbreviation of tungsten inert gas shielded welding. During the welding process, the tungsten electrode does not melt, and the arc generated between the tungsten electrode and the weldment is used as a heating source to melt the weld metal. At the same time, argon gas is sent out from the nozzle of the welding torch to protect the molten metal of the weld, and filler metal can be added as needed. It is called TIG welding internationally.
Ordinary DC argon arc welding machine: It can weld almost all metals except aluminum and magnesium, because this welding method uses an arc to heat the molten metal of the weld and then uses an inert gas to protect it. During the welding process, due to the protection of the inert gas, there are almost no other impurities and elements to participate in the welding process. It is basically completed by the process of melting and condensing the welded metal itself, so a fairly high-quality weld can be obtained.
At the same time, because the stable welding current of DC tungsten inert gas welding can be adjusted to a very small level, 3-5A can be used for stable welding, so it can weld extremely thin plates that cannot be welded by other common welding methods, including ordinary metals and their alloys.
AC argon arc welding machine: It is the best method for welding aluminum and magnesium among all the commonly used welding methods, because aluminum and magnesium are very easy to oxidize at room temperature. A layer of oxide film with a melting point far higher than the metal itself will be formed on the metal surface (the melting point of aluminum is 657℃, and the melting point of aluminum oxide is 2050℃), so it is difficult to weld aluminum, magnesium and their alloys with high quality by ordinary welding methods. In the negative half-wave of the current, the workpiece acts as an electrode and emits electrons outward, which will form a physical phenomenon called cathode fragmentation, breaking the refractory oxide layer on the surface of the workpiece. At the same time, due to the protection of inert gas, a new oxide layer will not be generated quickly; therefore, under the action of arc heat, relying on the surface tension of the molten liquid metal itself, it is easy to fuse the weld metal together.
Because AC argon arc welding does not require the addition of other chemicals and elements to remove the oxide film, it only relies on the arc to remove the oxide film. Under the pure welding arc, the metal connection can be completed by relying on the metal of the weldment itself, which will not change the composition of the weld metal too much, causing too large mechanical property differences between the weld metal and the parent metal. At the same time, there are no residual chemicals to corrode the weld metal, and it will not produce many welding defects like oxygen acetylene and electric welding. Therefore, argon arc welding is the best way to weld aluminum, magnesium and their alloys among all the current welding methods. When choosing tungsten electrodes, cerium tungsten electrodes are generally used for DC welding. When AC argon arc welding, pure tungsten grade has a small rectification effect, which is more effective in eliminating the DC component of the welding process, and it is easier to start and maintain the arc. Therefore, when welding aluminum workpieces, pure tungsten electrodes are used as much as possible; however, the high temperature resistance of pure tungsten electrodes is not as good as that of cerium tungsten electrodes. At the same time, the heat generated by tungsten electrodes during AC argon arc welding is higher than that of DC welding, so the tungsten electrode diameter selection requires a slightly larger diameter.
Disadvantages of argon arc welding: 1) Shallow melting depth and low production efficiency. 2) Inert gas is more expensive and the production cost is high.