Last updated: November 26th, 2019
If you are beginner surely will have the questions as
How many types of welding process?
What types of welding process fit for the beginner?
Our article will give for you definitions then you can choose the welding process fit for own.
Welding is a process in which two or more parts are joined permanently at their touching surfaces by a suitable application of heat and/or pressure. Often a filler material is added to facilitate coalescence. The assembled parts that are joined by welding are called a weldment. Welding is primarily used in metal parts and their alloys.
|Read more: What is the best welder for the beginner?|
|Read more: Best MIG welder for Begginer|
Arc Welding Process
Arc welding is a method of permanently joining two or more metal parts. The final welded joint has unit strength approximately equal to that of the base material. It consists of the combination of different welding processes wherein coalescence is produced by heating with an electric arc, and with or without the use of filler metals depending upon the base plate thickness. A homogeneous joint is achieved by melting and fusing the adjacent portions of the separate parts. The arc temperature is maintained approximately 4400°C. A flux material is used to prevent oxidation, which decomposes under the heat of welding and releases a gas that shields the arc and the hot metal. The second basic method employs an inert or nearly inert gas to form a protective envelope around the arc and the weld. Carbon dioxide, Argon, and Helium are the most commonly used gases.
Have several common welding processes fit for beginners as MIG, stick, and TIG, they quite are easy to learn.
Arc welding is divided into consumable and non-consumable electrode methods.
Consumable Electrode Methods
Stick Welding (Shielded Metal Arc Welding or SMAW)
Stick welding is also called as Shielded Metal Arc welding. This is the most basic of all welding types. Stick welding can be used for manufacturing, construction and repair work.
This is an arc welding process wherein coalescence is produced by heating the work piece with an electric arc setup between a flux-coated electrode and the work piece. This process is called stick welding because it uses welding sticks or rods that are made up of filler material and flux, the flux is used to protect the molten metal of the weld and the filler is then used to join two pieces of metal together.
Stick welding offers a very low-cost welding solution that requires minimal equipment. However, the quality of the final weld is not always the best as it can suffer from porosity, shallow penetration, cracking and it is highly vulnerable to severe weather and is generally less durable. Despite the fact that stick welding is a very old technique, it is still quite popular, especially in third world countries where expensive or new equipment is usually not widely available.
MIG (Metal Inert Gas) Welding or GMAW (Gas Metal Arc Welding)
MIG stands for Metal Inert Gas Welding (Gas Metal Arc Welding or GMAW) and it boils down to the concept of combining two pieces of metal together with a wire that is connected to an electrode current. The wire then passes through the welding stick which is shielded by an inert gas.
In this process, an inert gas such as argon, helium, carbon dioxide or a mixture of them is used to prevent atmospheric contamination of the weld. The shielding gas is allowed to flow through the weld gun. The electrode used here is in a wire form, fed continuously at a fixed rate. The wire is consumed during the process and thereby provides filler metal
A constant voltage and direct current power source are required for this method, and this is the most common industrial welding process. The MIG or GMAW process is suitable for fusing mild steel, stainless steel as well as aluminum.
Some of the advantages that MIG welding offers over the other welding techniques include ease of use and the lower degree of precision that is required by the operator in order to obtain decent welds. MIG ends up being much easier to master for operators as it is quite simple because the electrode is being automatically fed through the torch.
Read more: Best MIG welder for Begginer
Flux-Cored Arc Welding (FCAW)
This process is similar to the shielded-arc stick welding process with the main difference being the flux is inside the welding rod. Tubular, coiled and continuously fed electrode containing flux inside the electrode is used, thereby, saving the cost of changing the welding. Sometimes, externally supplied gas is used to assist in shielding the arc.
This type of welding is well-known for being extremely inexpensive and easy to learn, suitability for outdoor welding and windy conditions because no shielding gas is needed with the right type of filler. However, there are several limitations in its applications and the results are not often aesthetically pleasing as some of the other welding methods. The semi-automatic arc is often used in construction projects, thanks to its high welding speed and portability.
Best Flux-Cored Arc Welder
Forney Easy Weld 180 ST 120V/230 V Welder
Submerged Arc Welding (SAW)
This is another type of arc welding process, in which coalescence is produced by heating the workpiece with an electric arc set up between the base electrode and the workpiece. The molten pool remains completely hidden under a blanket of granular material called flux. The electrode is in a wire form and is continuously fed from a reel. Movement of the weld gun, dispensing of the flux and picking up of surplus flux granules behind the gun is usually automatic.
Used mostly on ferrous steel and nickel-based alloys, Submerged Arc Welding is a rather common Arc welding technique due to its minimal emissions of welding fumes and arc lights, making it safer than most welding processes. SAW results in deep weld penetration, and involves minimal preparation, making it a quick and efficient form of welding.
Non-Consumable Electrode Methods
TIG Welding (Gas Tungsten Arc Welding or GTAW)
This process is also known as tungsten–inert gas (TIG) welding. This is similar to the Gas Metal Arc Welding process. The difference being the electrode is non-consumable and does not provide filler metal in this case. A gas shield (usually inert gas) is used as in the GMAW process. If the filler metal is required, an auxiliary rod is used.
In TIG welding, the heat is created by running an electric current through a tungsten electrode, creating an arc that is then used to melt a metal wire in order to create the weld pool. TIG is most commonly used to weld stainless steel together, although other metals like magnesium, aluminum, copper, and nickel can be welded using TIG.
For this type of welding, the welder needs to have a lot of expertise as it’s a very complex process. This welding process is employed to carry out high-quality work when a superior standard finish is required, without making use of an excessive clean up by sanding or grinding.
Plasma Arc Welding (PAW)
This process is similar to TIG. A non-consumable electrode is used in this process. Arc plasma is a temporary state of the gas. The gas gets ionized after the passage of electric current and becomes a conductor of electricity. The plasma consists of free electrons, positive ions, and neutral particles.
Plasma arc welding differs from GTAW welding in the amount of ionized gas which is greatly increased in plasma arc welding, and it is this ionized gas that provides the heat of welding.
It positioning the electrode within the body of the torch, the plasma arc can be separated from the shielding gas envelope. The plasma is then forced through a fine-bore copper nozzle which constricts the arc and the plasma exits the orifice at high velocities (approaching the speed of sound) and a temperature approaching 28,000 °C (50,000 °F) or higher.
Best Plasma Cutter
PrimeWeld Ct520d 50 Amps Plasma Cutter
Electrogas welding (EGW)
Electrogas welding (EGW) is a continuous vertical position arc welding process developed in 1961, in which an arc is struck between a consumable electrode and the workpiece. Shielding gas is sometimes used, but pressure is not applied.
The arc in EGW is not extinguished and remains struck during the welding process. It is used to make square-groove welds for butt and t-joints, especially in the shipbuilding industry and in the construction of storage tanks.
Atomic hydrogen welding (AHW)
This is an older Arc welding process which is slowly being replaced by gas metal arc welding. circa 1930, the process of atomic hydrogen welding was invented by Irving Langmuir after his discovery of atomic hydrogen and involves placing two metal tungsten electrodes in a hydrogen atmosphere, leading to the hydrogen molecules breaking up and recombining in an explosion of heat which can reach temperatures above 3000 degrees Celsius.
The heat produced by this torch is sufficient to weld tungsten (3422 °C), the most refractory metal. The presence of hydrogen also acts as a shielding gas, preventing oxidation and contamination by carbon, nitrogen or oxygen, which can severely damage the properties of many metals. It eliminates the need of flux for this purpose.
Electroslag welding (ESW)
Known for being a very efficient, single-pass welding process that is generally used on thick, nonferrous metals. It is known for using an electric arc that is struck by wire and then fed into the welding puddle along with flux until the slag reaches the electrode and extinguishes the arc. As stated before, this technique is mostly used to weld thick pieces of metal as it requires a very high level of skill and it is very popular in maritime applications as well as the aerospace industry.
Electric Resistance Welding
Resistance welding is a group of welding process in which coalescence is produced by the heat obtained from the resistance of the work to the flow of electric current in a circuit of which the work is a part and by the application of pressure. No filler metal is needed in this process.
In general, resistance welding methods are efficient and cause little pollution, but their applications are limited to relatively thin materials and the equipment cost can be high (although in production situations the cost per weld may be low).
Oxyfuel Gas Welding (OFW)
Oxyfuel gas welding (OFW) is a group of welding processes which join metals by heating with a fuel gas flame with or without the application of pressure and with or without the use of filler metal.
OFW includes any welding operation that makes use of a fuel gas combined with oxygen as a heating medium. The process involves the melting of the base metal and a filler metal is used, by means of the flame produced at the tip of a welding torch.
Fuel gas and oxygen are mixed in the proper proportions in a mixing chamber which may be part of the welding tip assembly. Molten metal from the plate edges and filler metal, if used, intermix in a common molten pool. Upon cooling, they coalesce to form a continuous piece.
Weld bead size and shape and weld puddle viscosity are also controlled in the welding process because the filler metal is added independently of the welding heat source.
Oxyfuel gas welding is used for welding lead up to approximately 1/4 in. (6.4 mm) in thickness. The greatest field of application in the plumbing and electrical industry. The process is used extensively for soldering copper tubing.
Electron-Beam Welding (EBW)
Electron beam welding is defined as a fusion welding process wherein coalescence is produced by the heat obtained from a concentrated beam of the high-velocity electron. When high-velocity electrons strike the workpiece, kinetic energy is transformed into thermal energy causing localized heating and melting of the weld metal.
The electron beam generation takes place in a vacuum, and the process works best when the entire operation and the workpiece are also in a high vacuum of 10-4torr or lower. However, radiations namely ray, infrared and ultraviolet radiation generates and the welding operator must be protected.
Laser Beam Welding (LBW)
Laser beam welding is defined as a fusion welding process and coalescence is achieved by utilizing the heat obtained from a concentrated coherent light beam and impinging upon the surface to be joined. This process uses the energy in an extremely concentrated beam of coherent, monochromatic light to melt the weld metal.
Friction Welding (FRW)
In friction welding (solid state welding process) coalescence is produced by utilizing the heat obtained from the mechanically induced rotating motion between the rubbing surfaces. When the temperature at the interface of the two parts is sufficiently high, the rotation is stopped and increased axial force is applied. This fuses the two parts together. The rotational force is provided through a strong motor or a flywheel. In the latter case, the process may be called inertia welding.
Other Welding Processes
Other processes used in the industry are the following:
- Diffusion bonding (DB): Parts are pressed together at an elevated temperature below the melting point for a period of time.
- Explosion welding (EXW): The parts to be welded are driven together at an angle by means of an explosive charge and fuse together from the friction of the impact.
- Ultrasonic welding (USW) for metals: This process utilizes transverse oscillation of one part against the other to develop sufficient frictional heat for fusion to occur.