11 Welding Processes Illustrated: A Comprehensive Guide

There are different types of welding processes available today. Welding is the process by which two pieces of metals are joined together usually by the use of heat and sometimes with the addition of filler materials (metal) which make the joint stronger even than the parent metals. It can also be said to be a fabrication process that is used to joins metal materials, usually metals or thermoplastics using high heat to melt the parts together and fused them when cooled.

Welding process

The welding process has been classified into two; low and high-temperature meta-joining techniques. The low-temperature techniques include brazing and soldering. The base metal does not melt in this technique and at the high temperature, filler material is typically added to the joint to increase or support the lost portion of the parent metal. Filler materials can be stronger than the parent metal.

In high welding, pressure is also needed in joining with heat and produced a good joint. In addition, high welding, the filler used also required protection to avoid oxidation.

Welding is a hazardous process that can easily cause burns, vision damage, and intake of poisonous gas, electric shock, and exposure to ultraviolet radiation. Welding operations can be performed underwater, in outer space, and the open air. Furthermore, there are different types of welding processes with different energy sources.

Types of welding processes

below are the various types of welding processes:

Arc welding types of welding processes

The followings are the various types of arc welding:

Shielded metal arc welding

Shielded metal types of arc welding are the most common and most used welding today. Its process involves striking an electric arc between the workpiece and the metallic electrode. Because of the heat produced ting molten metal is transferred from the electrode to the joint surfaces. As mentioned earlier, arc welding can be performed on both DC and AC machines.

Gas-shielded arc welding

These arc welding types have become much useful over the years, as are automated and can leave more material at high efficiency.

Tungsten arc welding

Tungsten types of arc welding also use either DC or AC welding machines. They use electrode for the welding and filler material added to the joint and makes it stronger.

Consumable electrode gas-metal arc welding

These types of arc welding are used along with carbon dioxide shielding, widely used for welding steel.

Submerged arc welding

Submerged arc welding types are closely similar to gas shield arc welding. The major difference between them is that the gas shield has been changed with a granulated mineral material as a flux. in its working, materials is pack around the electrode which enables the arc to be invisible.

Plasma arc welding

Plasma arc welding types use hot plasma as their source of heat. They are also similar to gas shielded tungsten arc welding in terms of greater energy concentration, easier operator control, and improved arc stability.

Thermochemical types of welding processes

A thermochemical welding process is known to be gas welding and aluminothermic (thermite) welding process. below are the various types of Thermochemical welding processes:

Gas welding

The gas welding process is equally used when compared with metal-arc welding. The gas welding source of heat is a mixture of acetylene and oxygen which produces controlled different flame. The flames are named carburize, neutral, and oxidation flame. A neutral frame is generally used to prevent base metal from oxidation. Filler wire is added in form of cold filler. Over the years gas welding is now used specifically on sheet fabrication. However, gas welding is a very slow process.

Aluminothermic welding

These types of welding processes are a mixture of aluminum and iron oxide. It is ignited to produce a superheated liquid metal at about 2,800 degrees Celsius. This type of welding process is used to weld both ferrous and nonferrous metals and it is suitable for joining sections with large, compact cross-sections, such as rectangles and rounds.

Resistance welding

Resistance types of welding processes are known to be seam, spot, projection, flash, high and low-frequency welding. These processes are used for a very high rate of production.

Spot and seam welding required heat for joining which is generated at the interface by electrical resistance. Spot welds are suitable and mostly carry out on sheet metal that required overlap. This welding process is achieved in a short time using a voltage, high-current power as the heating service is applied to the joint through two electrodes with force. The strength of the joint is determined by the size and number of welds. Below are the various types of resistance welding:

Seam welding:

In seam welding, an electric current is placed to the metal surface that requires a joint to form a series of overlapping spots or a continuous seam. This welding process is used to weld structures where the spot is insufficient and mostly used to weld containers.

Projection welding

Projection welding is common when one part of the metal to be welded is a dent or pressed. The process enables multiple spots to be welded same time.

Flash welding

Flash welding processes are types of resistance welding that are carried out by clamping to parts that required joining. The parts ends are brought slowly together and then drown apart. The flashing process continued until the area that required joint is heated, the part will then be forced together and maintained pressure until the joint is formed and cooled.

Low and high-frequency resistance welding

These types of resistance welding are widely used in manufacturing tubing. Its joint is longitudinal in the tube created from a metal squeezed into shape with edges abutted. The welding heat is controlled by the current passing through work and the speed at which the tube goes in rolls.

Cold welding

Cold welding is accomplished by joining materials without the use of heat but simply by pressing the required parts together. The joint area has to be well prepared and pressure of 35 to 90 percent is needed for easy deformation of the joint. Pressure is applied by a rolling stand or pneumatic tooling and punch presses. Aluminum required pressure of about 1,400,000 to 2,800,000 kilopascal are needed to produce a joint. However, other metals need higher pressures.

Friction welding

Friction welding is another type of welding that is performed by bringing the workpiece together under load with one part revolving quickly. The heat is created at the interface until it becomes plastic. The rotation is then stopped and the load is increased to produce the joint. As a result of strong joints with the aid of the plastic deformation process may be called a variation of pressure welding. The welding process is regulated for as the temperature at the joint rises the friction coefficient reduces which helps in preventing overheating.

Laser welding

Laser welding is performed by emitting light energy from a laser source to place on a workpiece to fuse them. Laser types of welding processes are useful in miniaturized electrical circuitry. The availability of lasers is limited and their uses have been restricted in some areas. Its speed and the thickness that can be welded are controlled by the thermal conductivity of the metal by and the metal vaporization of the surface is avoided. It can be applied to very thin materials of about 0.5mm.

Diffusion bonding

Diffusion bonding is carryout by applied pressure of an elevated temperature within a period of time. The pressure is expected to be applied at fewer rates to cause 5% of deformation to pertained finish machine parts. This welding process is extensively used in aerospace industries for joining shapes and materials.

Electron-beam welding

Electron-beam welding are types of welding processes that bombard the workpiece with a dense stream of high-velocity electrons which converts the electron’s energy into heat. The workpiece is placed in an evacuated chamber to allow good electron travel and a beam-focusing device is included in this type of welding. Intense heat is created that nearly vaporizes a hole through the joint. Very high voltages of about 150 kilovolts are used in making an extremely narrow deep-penetration weld. An automatic transverse device helps in positioning the workpiece accurately. For example, a material of 13mm thick would only be 1mm wide. Typically, an electric-beam welding speed is 125 to 250cm per minute.

Ultrasonic welding process

These types of welding are performed by clamping the two pieces that required welding on an anvil and a vibrating probe. This vibration helps in raising the temperature at the interface and the weld is achieved. The weld can be performed in 0.08 seconds on thin wires and up to 1 second with material 1.3 thick. The ultrasonic welding process is extensively used to lend bonding to integrated circuitry, transistor canning, and the body of aluminum can.

Explosive welding

These types of welding are achieved by impacting two plates together under an explosive force at high velocity.  One of the plates is laid on a strong surface made of a heavier steel plate. The other plate is then carefully placed at an angle of 5 degrees to the lower plate with a sheet of explosive material at the top. Heat is obtained from the hinge of the two plates and the weld takes place by rapid plastic deformation of the material at the interface. The join is caused by a jetting action of metal between the plates, making the weld have a wave appearance.

Forge welding process

These types of welding processes are fashion techniques that have been applicable from the earliest uses of iron. The process is done by pressing or hammering hot pieces of heat. At first, it makes use of small pieces of iron into larger useful ones by joining them. Forge welding temperature before hammered or pressed together. This welding process is used by blacksmith mostly in making items like sword and chain.

That is all for this article, where the different types of welding processes are discussed. I hope you get a lot from the reading, if so, kindly share with other students. Thanks for reading, see you next time!