According to the different electrodes, argon arc welding is divided into two types: molten argon arc welding and non-melting argon arc welding.
1. Working principle and characteristics of non-melting argon arc welding
Non-melting argon arc welding is the arc burning between a non-melting pole (usually a tungsten pole) and a workpiece. An inert gas (usually argon) that does not chemically react with the metal flows around the welding arc to form a The hood is protected so that the tungsten tip, the arc and the molten pool and the metal that is already at a high temperature are not in contact with the air, preventing oxidation and absorbing harmful gases. Thereby forming a dense welded joint, the mechanical properties are very good.
The characteristics of tungsten argon arc welding are as follows:
(1) It is possible to weld metals and alloys that are very chemically active. The inert gas argon or helium does not chemically react with chemically active aluminum, titanium, magnesium, copper, nickel and their alloys even at high temperatures, and is insoluble in liquid metals. Welding methods protected by slag (such as hand arc welding or submerged arc welding) are difficult to weld these materials, or they cannot be welded at all.
(2) A welded joint that can be obtained. The weld metal obtained by this welding method has high purity, less gas and gas metal inclusions, and less welding defects. Low-carbon steel, low-alloy steel and stainless steel, which require high quality of weld metal, are commonly used for welding.
(3) Weldable thin parts and small pieces.
(4) One-side welding can be double-sided forming and all-position welding.
(5) Low welding productivity.
The welding current used in tungsten argon arc welding is limited by the tungsten current carrying capacity, the arc power is small, the arc penetration force is small, the penetration depth is shallow and the welding speed is low, and the tungsten electrode needs to be frequently replaced during the welding process.
2. Working principle and characteristics of argon-shielded arc welding
The argon-shielded welding wire is fed through the wire wheel, the conductive nozzle is electrically conductive, an electric arc is generated between the base metal and the welding wire, the welding wire and the base material are melted, and the arc and the molten metal are protected by an inert gas argon gas for welding. It differs from tungsten argon arc welding: one is the wire as the electrode, and is continuously melted and filled into the molten pool to form a weld after condensation; the other is the shielding gas, with the technical application of the argon arc welding, the shielding gas A wide range of applications have been developed from a single argon gas, such as Ar% 2080% + CO 220% argon-rich shielding gas. Usually the former is called MIG and the latter is called MAG. In terms of its operation mode, the most widely used ones are semi-automatic argon-shielded arc welding and argon-rich gas mixture welding, followed by automatic argon-shielded arc welding.
Compared with tungsten argon arc welding, argon-shielded arc welding has the following characteristics.
(1) High efficiency. Because of its high current density, heat concentration, high deposition rate, and fast welding speed. In addition, it is easy to lead the arc.
(2) Strengthen protection. Because the arc is strong and the smoke is large, it is necessary to strengthen the protection.
Post time: Jan-04-2019