The Gas Tungsten Arc Welding Process Can Be Used to Join Nearly All Types and Thicknesses of Metal
Welding is ane of the joining processes that can efficiently and economically get together two or more metallic or non-metallic parts permanently. With the extensive development throughout the years, a big number of such processes has evolved in order to cater the need to bring together a large variety of materials in innumerable means. Gas metal arc welding (GMAW) is one such process where metallic materials are joined permanently past melting faying surfaces of the components by ways of electric arc established betwixt electrode and workpiece. The consumable electrode, in the grade of small-scale diameter wire, is continuously fed at a predefined rate for depositing necessary filler metal to make full the root gap.
In order to stabilize the arc and also to protect the hot molten metal pool below this arc from oxidation and other contamination, proper shielding gas is used to shield or cover unabridged welding zone surrounding this arc. This shielding gas tin can exist chemically inert one or tin contribute in many relevant backdrop past actively participating in the welding process. Appropriately GMAW can be classified into two groups—Metal active gas (MAG) and Metal inert gas (MIG) welding. So MIG and Mag both are basically variants of GMAW process; only difference lies on the shielding gas used in those processes.
As the name suggest, Metal Inert Gas (MIG) welding process utilizes suitable inert gas for shielding purpose during welding. Such gas is mainly argon or helium, or a mixture of these two in dissimilar proportions. Since these gases are chemically inert thus they remain stable even at farthermost arc oestrus. Therefore they do not contribute in altering any weld characteristics autonomously from protecting the weld dewdrop and electric arc from whatever external influence.
On the other hand, Metal Active Gas (Mag) welding utilizes an active gas mixture every bit shielding gas. For case, a suitable mixture of carbon di-oxide (CO2) and oxygen (O2) along with other comparatively stable gases like argon, helium, nitrogen, etc. Also fulfilling basic requirement of shielding gas, such active gases tin intermission down due to arc heating and subsequently induce various chemical elements on weld dewdrop that tin raise joint backdrop. It likewise contributes in stabilizing arc, reducing spatter level, etc. Various differences betwixt MIG welding and Mag welding are given below in table format.
Tabular array: Differences between MIG welding and MAG welding
| MIG welding | Mag welding |
|---|---|
| MIG welding is ane type of GMAW process that utilizes inert gases (Ar or He) as shielding gas. | MAG welding is another type of GMAW process that utilizes a mixture of inert and active (O2, CO2) gases as shielding gas. |
| No mechanical or chemical property changes due to shielding gas remains stable. | Shielding gas can alter mechanical and chemical properties of weld bead by inducing diverse elements on information technology. |
| Inert gas cylinder is costlier and thus MIG welding is also costlier. | Shielding gas is comparatively cheaper and thus Magazine welding is economical. |
| This procedure is suitable for welding non-ferrous materials like aluminum. | Information technology is suitable for welding of ferrous metals, especially stainless steel. |
Characteristics of shielding gas: As the name suggests, metallic inert gas (MIG) welding utilizes only inert gas similar argon or helium. Such gases remain stable even at extreme arc temperature. Metallic active gas (Mag) welding utilizes a mixture of inert gas and active gases as shielding gas. Such active gas mainly includes oxygen and carbon di-oxide. The mixing proportion betwixt inert and active gases tin can significantly vary based on many parameters like base metal and its thickness, filler metal, root gap, welding polarity, intended backdrop of weld bead, etc. Sometimes environmental condition likewise governs this proportion.
Adequacy of altering properties of weld bead: Inert shielding gases remain stable during welding and thus practice not induce any chemical elements on weld bead. Nonetheless, active gases can break down nether extreme arc temperature and tin afterward induce relevant chemical elements on weld bead. This leads to alter in chemical and mechanical properties of joint. For example, while joining low carbon steel (like mild steel) using carbon di-oxide rich shielding gas, carbon inclusion may occur and this tin can heighten surface hardness of joint. Therefore, MIG welding cannot change weld bead properties; while, Magazine can do the same.
Cost of shielding gas and application expanse: In GMAW, shielding gas menses rate in the guild of 10 – 20L/min is utilized. Cylinders, filled with industrially pure shielding gas, is insufficiently costlier and thus MIG welding is one costlier process. It is primarily used for welding non-ferrous materials like aluminum. Oxygen based agile gas is not favored when parent materials are not-ferrous considering of loftier chances of oxidation. In this sense, MAG is economical and preferred for welding of ferrous metals, especially stainless steel.
Scientific comparing among metal active gas (Mag) and metallic inert gas (MIG) welding is presented in this commodity. The author also suggests you lot to go through the following references for better understanding of the topic.
- Metal Inert Gas (MIG) / Metal Active Gas (Magazine) Welding by linde-gas.com.
- What is the deviation between MIG and MAG past twi-global.com.
Source: https://www.differencebox.com/engineering/difference-between-metal-inert-gas-and-metal-active-gas-welding/
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