Welding is the process by which two pieces metals are joined together usually by the use of heat and sometimes with addition of filler materials (metal) which make the joint stronger even than the parent metals.
Welding 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 when cooled.
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 techniques and in the high temperature, filler material is typically added the joint to increase or support the lose portion of the parent metal. The filler material can be stronger than the parent metal.
In the high welding, pressure is also needed to in joining with heat and produced a good joint. In addition, high welding, the filler used also required a protection to avoid oxidation.
Welding is a hazardous process that can easily cause burns, visions damage, and intake of poisonous gas, electric shock and exposure to ultraviolent radiation. Welding operation can be performed under water, outer space, and in open air. Furthermore, there are different types of welding process with different energy sources.
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- 1 What are the types of welding process?
- 2 Join our Newsletter
- 3 Ultrasonic welding process
What are the types of welding process?
As you can see i have just explained what welding is, now am about explaining the types of welding process that exist. take a deep breath and gain some knowledge.
Arc welding types of welding process:
1. Shielded metal arc welding is the most common and most used welding today. It process involves strucking an electric arc between the work piece and the metallic electrode. Because of the heat produced ting molten metal are transferred from the electrode to the joint surfaces.
As mentioned earlier, arc welding can be performed on both DC and AC machine.
2. Gas-shielded arc welding has become much useful over the years, as is automated and can leave more material at high efficiency.
3. Tungsten arc welding also uses either DC or AC welding machine. It uses electrode for the welding and filler material added to the joint and makes it stronger.
4. Consumable electrode gas-metal arc welding with a carbon dioxide shielding is widely used for welding steel.
5. Submerged arc welding is closely similar to gas shield arc welding, their difference is that the gas shield has been changed with a granulated mineral material as a flux. The material is pack around the electrode which enables the arc to be invisible.
6. Plasma arc welding uses hot plasma as its source of heat. It is similar to gas shielded tungsten arc welding in terms of greater energy concentration, easier operator control and improved arc stability.
Thermochemical types of welding process:
Thermochemical welding process is known to be gas welding and aluminothermic (thermite) welding process.
1. 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 year gas welding is now used specifically on sheet fabrication. However, gas welding is a very slow process.
2. Aluminothermic welding process is a mixture of aluminum and iron oxide. It is ignited to produce a superheated liquid metal at about 2,800 degree Celsius. This type of welding process is used to weld both ferrous and non ferrous metals and it is suitable for joining sections with large, compact cross sections, such as rectangles and rounds.
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Resistance types of welding process:
Resistance welding processes are known to be seam, spot, projection, flash, high and low frequency welding. These processes are used for 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 carryout on sheet metal that required overlap. This welding process is achieved in a short time using a voltage, high-current power as the heat service applied to the joint through two electrodes with force. The strength of the joint is determined by the size and number of welds.
1. Seam welding : In seam welding, electric current is placed to the metal surface that requires joint to form a series of overlapping spots or a continuous seam. This welding process is used to weld structures where spot is insufficient and mostly used to weld container.
2. Projection welds is common when one parts of metal to be welded is dent or pressed. The process enables multiple spots to be welded same time.
3. Flash welding is another type of resistance welding which is 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.
4. Low and high-frequency resistance welding is another type of welding widely used in manufacturing of tubing. It 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 speed at which the tube goes in rolls.
- Foundry work and Processes
- Different types of Foundry tools and equipment
- Types of foundry patterns (casting patterns) and how its works
- Types of casting defects and their causes
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 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 is another type of welding that is performed by the bringing the work piece 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 joint with the aid of plastic deformation process may be called variation of pressure welding. The welding process is regulated for as the temperature at the joint rises the friction coefficient reduces which help in preventing overheating.
Laser welding is performed by emitting light energy from a laser source to place on a work piece to fuse them together. This welding process is useful in the miniaturized electrical circuitry. Availability of lasers are limited and it use have been restricted in some areas. It 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 avoid. It can be application to very thin materials of about 0.5mm.
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 in order to pertained finish machine parts. This welding process is extensively used in aerospace industries for joining shapes and materials.
Electron-beam type of welding process
Electron-beam welding is another type of welding that bombard the work piece with a dense stream of high velocity electron which convert the electron’s energy into heat. The work piece is placed in an evacuated chamber to allow good electron travel and a beam-focusing device is included in this type of welding. An 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 work piece accurately. For example, a material of 13mm thick would only be 1mm wide. Typically, an electric-beam welding speed are 125 to 250cm per minute.
Ultrasonic welding process
Ultrasonic welding is performed by clamping the two pieces that required welding on an anvil and a vibrating probe. The vibration helps in raising the temperature at the interface and the weld is achieved. The weld can be performed in 0.08 second on thin wires and up to 1 second with material 1.3 thick. Ultrasonic welding process is extensively used lend bonding to integrated circuitry, transistor canning, and body of aluminum can.
Explosive welding is 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 heavier steel plate. The other plate is then carefullu placed at an angle of 5 degree to the lower plate with a sheet of explosive material at the top. The heat is obtained from the hinge of the two plates and the weld take place by a 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 to have a wave appearance.
Forge welding process:
Forge welding process is fashion techniques has 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 one 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.
And that is it for this article, types of welding process. i hopefully believed your goal here is achieved. Ask question via our comment box and don’t forget to share with others. thanks for reading!