What is Welding?
Welding is a process of joining two or more parts by heating the parts or joints.
There are different types of welding processes. There are even many categories for the welding. They are represented below-
There are primarily 5 categories of welding. They are-
2. Oxygen Gas Welding Process
3. Resistance Welding Process
4. Solid State Welding Process
5. Other Welding Process
ARC WELDING PROCESS-
1. Atomic Hydrogen Welding-
Two types of metal electrodes are used in Atomic Hydrogen Welding. These electrodes are used in Hydrogen atmosphere.
2. Bare Metal Arc Welding-
Consumable electrodes are used in Bare Metal Arc Welding. These electrodes must be changed after they completely vanish. There will be no further gas used for shielding.
3. Carbon Arc Welding-
Carbon electrodes are used in Carbon Arc Welding. Copper may be used but is limited to some applications only.
4. Flux Cored Arc Welding-
The Flux Cored Arc Welding is same as Bare Metal Arc Welding but flux is used. The electrodes are consumed continuously.
5. Gas Metal Arc Welding-
The Gas Metal Arc Welding is same as Bare Metal Arc Welding but additional shielding gas is used. The electrodes are consumed continuously.
NOTE- The comparison is made due to fast remembering of all the types of Welding.
6. Gas Tungsten Arc Welding-
Non consumable electrodes are used. Due to these, the process is very slow but high quality of welds can be obtained. Mostly used for Aerospace designs.
7. Plasma Arc Welding-
Non consumable electrodes are used. The process is very slow but of high quality. Mostly used for tubing and instrumentation.
8. Shielded Metal Arc Welding-
This uses consumable electrodes for welding but continuous welding is employed with suitable flux for respective material weldings.
9. Submerged Arc Welding-
Submerged Arc Welding is same as Shielded Metal Arc Welding but is submerged in granular flux rather than normal flux.
OXYFUEL GAS WELDING-
1. Air Acetylene Welding-
In this welding process, welding is done with the help of chemicals. The disadvantages of the process are far high than advantages, so this is not popular.
2. Oxyacetylene Welding-
In this welding, welding is done with combustion of acetylene and oxygen. This combustion produces a very high temperature with which we can weld accurately. The equipment is also very cheap when compared to others. This welding is used primarily for maintenance works.
3. Propane Welding-
This welding is also known as Oxygen Welding. It consists of producing high temperature with the help of oxygen or propane flame.
4. Oxyhydrogen Welding-
This welding produces very high temperature with the help of combustion of oxygen and hydrogen in accurate quantities.
5. Pressure Gas Welding-
First, the gas flame produces very high temperatures. Second, pressure is used to make the desired weld and fixed accurately. This is not generally used now-a-days.
1. Resistance Spot Welding-
Two sharp pointed electrodes are used to weld two or more surfaces or joints by applying pressure on both the sides. Mostly used for thin materials and finds application in Automobile and Aerospace industry.
2. Resistance Seam Welding-
Two wheel shaped electrodes are used for welding process. These two electrodes are rolled on the materials which at the same time high pressure and current is applied. This is also widely used type of welding.
3. Projection Welding-
There are some projections to be determined and welding is done at those localized points. This may be Semi-Automatic or Automatic.
4. Upset Welding-
Butt joint surfaces are heated to some extent and are brought together by pressure. This is Upset Welding. This welding is employed only for butt joint surfaces.
The below types of weldings are not normally employed unless it is an emergency and needy case.
SOLID STATE WELDING-
1. Coextrusion Welding-
Dissimilar metals are joined with the help of Coextrusion welding. These are joined by placing in the same die. This is a very cheap process and used for joining small alloys.
2. Cold Pressure Welding-
Soft alloys cannot be joined with the help of Solid State Welding. For soft alloys, Cold Pressure Welding is used. The process is done below the melting point of the alloys used.
3. Diffusion Welding-
This is a very special welding and in this type of welding, no weld line is visible. This is employed for Titanium pump impeller wheels.
4. Explosion Welding-
The Explosion Welding is same as Coextrusion Welding. The only difference between Coextrusion and Explosion welding is the process employed. This is due to explosion and Coextrusion Welding is due to the die.
5. Electro Magnetic Pulse Welding-
The materials to be welded are accelerated by means of electromagnetic forces. The oxides are completely expelled during the collision of the materials.
6. Forge Welding-
This is the oldest welding process used only for Damascus steel. Oxides are removed with the help of flames or flux.
7. Friction Welding-
Friction is the type of energy loss which will be in the form of heat energy. Sufficient pressure is provided with oxides at the place where heat is generated due to friction.
8. Friction Stir Welding-
A non consumable is used for this welding. It is traversed all along the joint line. This is mostly employed for ship building, aerospace, automotive and railway rollings industries.
9. Hot Pressure Welding-
Two metals are made hot that has to be welded and certain enough pressure is applied on the materials. The temperature must be below the melting point and the process must be done in vacuum or any inert atmosphere.
10. Hot Isostatic Pressure Welding-
Normally compressed gas is used to apply pressure or by hydraulics. In this type of welding, inert gas is used for pressure inside the pressure vessel.
11. Roll Welding-
This welding includes two bimetallic materials welding. These two materials are rolled by applying high pressure and high temperature. This can be employed only for two dissimilar metals.
12. Ultrasonic Welding-
High frequency ultrasonic waves are generally used for welding process. This energy gets transferred to foils or plastics that cause welding.
1. Electron Beam Welding-
The process is very fast and the quality obtained is also very high. The only disadvantage is the cost of the equipment is very high.
2. Electroslag Welding-
Very thick work pieces are difficult to weld. This welding can be used to weld even thick materials quickly and continuously. Most used for Heavy Plate Fabrication.
3. Laser Beam Welding-
This welding is same as Electron Beam Machining. The quality obtained from this welding is little bit high compared to Electron Beam Welding. So this is mostly used for automobile equipment weldings.
4. Laser Hybrid Welding-
Laser Hybrid Welding is the combined process of Laser Beam Welding and Gas Metal Arc Welding. It is used to cover a gap of 2 mm between the plates.
5. Percussion Welding-
It follows an electrical discharge which makes the metal heated to a very high temperature, normally to the melting point. This welding is used for components of very small size namely gears.
6. Thermite Welding-
Thermite welding is done due to the exothermic reaction. Exothermic reaction is the process where heat is expelled during reaction.
7. Electrogas Welding-
Consumable electrodes are used and continuous welding is done in Electrogas Welding. This welding is possible only for steel. Usually employed for storage tanks and ship building.
8. Stud Arc Welding-
The studs are welded fore the materials. These are heated to a higher temperature and then pressure us applied. As the welding is done to the studs, the welding is named as Stud Arc Welding.
As you keenly observe, the names of the welding types itself consists of the process done in that welding. So just try to remember the types and you will automatically grasp the process indulged in it.
These are the different types of Welding processes.