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Differences between TIG, MIG, and MAG welding: 1. In TIG welding, one hand holds the welding torch while the other holds the welding wire; it is suitable for manual welding on a small scale or for repairs. 2. MIG and MAG: The welding wire is fed from the welding gun through an automatic wire feeding mechanism, making them suitable for automated welding; however, they can also be used manually. 3. The main difference between MIG and MAG lies in the shielding gas. The equipment is similar, but the former is generally protected by argon gas and is suitable for welding non-ferrous metals ； The latter generally contains carbon dioxide as an active gas in argon, and is suitable for welding high-strength steels and high-alloy steels. 4. TIG and MIG are both gas-shielded welding processes, commonly known as argon arc welding. Inert gases can be argon or helium, but since argon is cheaper, it is more commonly used; therefore, inert gas arc welding is generally referred to as argon arc welding. Comparison between MIG welding and TIG welding Comparison between MIG welding and TIG welding MIG welding (Metal Inert-Gas Welding): In English, it is referred to as metal inert-gas welding. It is an arc welding method that uses a molten electrode, with an external gas serving as the medium for the arc; this gas also protects the molten metal droplets, the weld pool, and the metal in the high-temperature area during welding. It is also known as gas-shielded metal arc welding. The arc welding process that uses solid wire and inert gas (Ar or He) for protection is called Metal Inert Gas welding, abbreviated as MIG welding. MIG welding differs from this in that a metal wire is used instead of the tungsten electrode in the welder. The rest is the same as TIG welding. Therefore, the welding wire is melted by the arc and fed into the welding area. Electrically driven rollers feed the welding wire from the spool into the welding torch as required for welding. The heat source is also a direct current arc, but its polarity is exactly the opposite of that used in TIG welding. The shielding gas used is also different; 1% oxygen is added to argon in order to improve the stability of the arc. Like TIG welding, it can weld almost all metals, and is particularly suitable for welding materials such as aluminum and aluminum alloys, copper and copper alloys, as well as stainless steel. There is almost no oxidation or burnout during welding, only slight evaporation loss, and the metallurgical process is relatively simple. TIG welding (Tungsten Inert Gas Welding) is also known as non-consumable electrode inert gas tungsten shielded welding. Whether in manual or automatic welding of stainless steel with a thickness of 0.5–4.0 mm, TIG welding is the most commonly used welding method. TIG welding with filler wire is commonly used for root welding of pressure vessels, as TIG welding provides good airtightness which helps to reduce pores in the welds during the welding process of such vessels. The heat source for TIG welding is a direct-current arc; the operating voltage ranges from 10 to 95 volts, but the current can reach 600 amps. The correct way to connect a welding machine is to connect the workpiece to the positive pole of the power supply, with the tungsten electrode in the welding torch serving as the negative pole. The inert gas is generally argon. Inert gas is fed in through the welding torch to create a shield around the arc and over the weld pool. To increase heat input, 5% hydrogen is generally added to argon. However, when welding ferritic stainless steel, hydrogen cannot be added to the argon gas. The gas consumption is about 3 to 8 liters per minute. During welding, in addition to blowing inert gas from the welding torch, it is advisable to also blow gas from beneath the weld in order to protect the back side of the weld. If necessary, welding wire with the same composition as the austenitic material to be welded can be filled into the weld pool; when welding ferritic stainless steel, type 316 filler is typically used. Thanks to the protective effect of argon, which shields the molten metal from the harmful effects of air, TIG welding is widely used for welding highly oxidizable non-ferrous metals such as aluminum and magnesium and their alloys, stainless steel, superalloys, titanium and its alloys, as well as refractory reactive metals like molybdenum, niobium, and zirconium. For ordinary materials such as carbon steel and low-alloy steel, TIG welding is generally not used, except in situations where high requirements are placed on the quality of the weld.