15 Gas Metal Arc Welding Advantages and Disadvantages | Application of Gas Metal Arc Welding
What is Gas Metal Arc Welding (GMAW)? Gas Metal Arc Welding Advantages and Disadvantages | Application of Gas Metal Arc Welding
What is Gas Metal Arc Welding (GMAW)?
Gas metal arc welding (GMAW), also known as a metal inert gas (MIG) and metal active gas (MAG), is a welding procedure in which an electric arc formed between a consumable MIG wire electrode and the workpiece metal(s), heating them and forcing them to fuse (melt and join).
GMAW is a type of arc welding that creates an arc between a continuous filler metal electrode and the weld pool.
The method is used without applying pressure and with shielding from an externally supplied gas.
The GMAW can be used in semiautomatic, machine, or automatic modes. It operates on a constant voltage (CV) power supply and transfers metal from the electrode to the work via either the short-circuiting, globular, or spray processes.
A shielding gas, in addition to the wire electrode, is sent through the welding gun, protecting the operation from ambient contamination.
The method might be semi-automatic or fully automated. With GMAW, a constant voltage, direct current power source is most typically employed, but constant current systems and alternating current can also be used.
In GMAW, there are four basic metal transfer methods: globular, short-circuiting, spray, and pulsed spray, each with specific features and corresponding advantages and drawbacks.
GMAW was first created in the 1940s for welding aluminum and other non-ferrous materials, but it was quickly adapted to steels since it gave faster welding time than previous welding methods.
The high expense of inert gas prevented its usage in steels until several years later, when semi-inert gases like carbon dioxide became prevalent.
Further advancements in the 1950s and 1960s increased the method’s adaptability, and as a result, it became a popular industrial process.
Today, GMAW is the most commonly used industrial welding method, due to its versatility, speed, and relative ease of adaptability to robotic automation.
It is rarely utilized outdoors or in other areas of moving air, in contrast to welding procedures that do not use a shielding gas, such as shielded metal arc welding.
Flux cored arc welding, a comparable procedure, frequently does not require a shielding gas and instead employs an electrode wire that is hollow and filled with flux.
MIG welding has been used successfully in industries like aircraft, automobile, pressure vessel, and ship building.
Application of Gas Metal Arc Welding
The approach can be used to weld carbon, silicon, and low alloy steels, stainless steels, aluminum, magnesium, copper, nickel, and their alloys, titanium, and other metals.
There are several applications of gas metal arc welding. They include;
1. Welding of couplings
Couplings are used in the automotive industry to join two units together, with the purpose of being able to move the one unit with ease or put them in motion. The most common technique used is GMAW, however it can be FCAW as well.
2. Welding of metal pipes
GMAW is the most popular method used for welding of piping in industries such as chemical and food processing, petroleum and gas industries, and military applications.
3. Welding of pressure vessels
GMAW is used to weld structural parts of pressure vessels in aeronautics and shipbuilding industries. It is also used to weld oil pipes and liquefied natural gas tanks.
4. TIG welding with filler metal
Tungsten inert gas welding (TIG) is a very popular method of gas metal arc welding (GMAW). It is used to weld the metal filler material, such as nickel.
5. Building and Bridge construction;
GMAW is used for expansion box joints, lugs and anchor attachments to the structural steel.
6. Welding of aluminum piping
GMAW is the most popular welding technique used for aluminum pipes in the oil and gas industry. It is also used for joining of glass in the construction industry.
7. Welding of copper piping
GMAW is used to weld copper piping systems, such as domestic and industrial hot-and cold-water supply systems, process circuits, drain lines and sanitary systems.
Gas Metal Arc Welding Advantages and Disadvantages
Gas Metal Arc Welding Advantages
1. Minimal cleaning (no slag)
With this method, the weld puddle is not contaminated by slag, and therefore, no cleaning is required.
It is important to note that the weld puddle should be sufficiently covered up to avoid any contaminants getting into the weld pool.
2. Good for through-hardened or dirty steel with risk of porosity
Gas metal arc welding has a tendency to give good fusion characteristics in higher-alloy steels with serious inclusions or rusting because it does not oxidize or reduce the base metal.
3. GMAW can be fully automatic, resulting in higher productivity.
GMAW can also be fully automated. This increases productivity and reduces human error.
4. GMAW tends to produce a better-quality weld.
Gas metal arc welding tends to produce a better-quality weld due to the increased melting point and its resistance to oxidation, which results in a cleaner fusion of metals as compared to flux core arc welding (FCAW).
GMAW utilizes a continuously fed electrode which in turn minimizes defects since no restarts are required
5. Easy to control electrode consumption
GMAW machines are easy to control, enabling you to monitor the electrode consumption rate and ensure that you do not use excess amount. This minimizes wastage and ensures that you spend less cash in the long run.
6. GMAW can be used for all metals and alloys.
Gas metal arc welding can be used for all metals and alloys, but the results will always vary based on the materials attached. We recommend that you receive training before using this method to weld sensitive materials like stainless steel.
7. GMAW machines are easy to use.
The GMAW machines are easy to use as long as you are sure about how you will handle them while welding.
8. GMAW produces lower levels of fumes as compared to FCAW or SMAW.
GMAW produces lower levels of fumes as compared to FCAW or SMAW, due to the reduced electrode consumption.
9. GMAW is safer.
Gas metal arc welding is safer because it has a much higher electrode potential than other methods, and when an arc starts, it burns up any moisture that was present in the air, so there is no risk of explosion or fire.
10. GMAW has good weld penetration, allowing for good strength with smaller weld sizes.
GMAW has good weld penetration, allowing for good strength with smaller weld sizes.
GMAW Disadvantages
1. Welding is costly and complex more so than SMAW
Generally, GMAW is more expensive than SMAW as the consumables is expensive. However, the cost of repairing machines after welding such as GMAW is higher.
2. GMAW has a long learning curve that requires constant training
Gas metal arc welding requires constant training to handle the equipment properly for best results and to prevent accidents.
The whole process of welding can be dangerous if not controlled properly.
3. Sensitive to air drafts and loss of shielding.
A potential problem with GMAW welding is the loss of shielding. Although shielding gases are used, entrained air can enter the weld with contact.
The welding operation is not affected as long as an adequate amount of shielding gas remains within the welding chamber.
All welding operations are susceptible to air drafts, however, any physical damage to the machine will lessen the effectiveness of this method.
4. GMAW-S is subject to a lack of fusion
Gas metal arc welding- submerged (GMAW-S) is subject to lack of fusion in different types of metals. The weld is also not as strong as with other methods.
5. GMAW is less portable than SMAW
Gas metal arc welding is less portable than SMAW. The bulky equipment and the high speed of the welding process make it impossible to carry them around with you when travelling.
6. GMAW is more maintenance-intensive
Gas metal arc welding has higher maintenance costs, as compared to SMAW or FCAW. The purpose of shielding gases in these methods is to protect the weld area from contamination, so they are usually highly corrosive, and therefore, require regular cleaning after use.
Gas metal arc welding FAQs
1. What is GMAW?
Gas metal arc welding (GMAW) is a metal joining technique, which is used for the welding of metals such as steel, stainless steel, copper and aluminum.
It uses an electrode to heat the base material until the molten metal, commonly known as weld pool forms and join the two metal components together.
The molten pool can be made from either bare wire or a coated electrode.
2. What are the three GMAW processes?
The process by which the molten metal at the wire electrode’s end is transmitted to the workpiece has a considerable effect on the weld properties in GMAW.
GMAW has three metal transfer modes: short-circuiting transfer, globular transfer, and spray transfer.
3. What are the applications of GMAW processes?
GMAW is used in the automotive sector for both manufacturing and maintenance. For time-saving production operations, robotic assembly lines employ GMAW.
GMAW is used by pipefitters to weld pipe joints. GMAW is used in the rail industry for quick, long-lasting repairs or building of railroad tracks.
4. What is another name for GMAW?
Gas metal arc welding (GMAW), also known as metal inert gas (MIG) welding, uses a continuous solid wire electrode that travels through the welding gun, which is accompanied by a shielding gas to protect it from contaminants.
5. Is Arc welding more efficient than TIG welding?
TIG welding creates stronger, cleaner, and more exact welds than MIG or other Arc welding processes.
However, different welding jobs may necessitate the use of different procedures; while TIG welding is normally stronger and of higher quality, you should employ MIG or another process if the job necessitates it.
