Welding is a process of joining two materials where their multiple parts are connected through heat and pressure. The joined parts are called a parent material, whereas the material used for joining them is called as filler or consumable. You will see that welding is majorly done on metals and thermoplastics, but some people also do it on wood.
Certain materials require a specific process and technique, making it necessary for welders to know about the properties of different materials. The composition of consumables is usually chosen to be similar to the parent material, which forms a homogenous weld, but sometimes it could differ. In this article, you will discover various other things that you should know about welding.
Welding on different materials:
Metals are joined by three different processes, namely welding, soldering, and brazing. In welding, you melt the base material with high heat, whereas in brazing and soldering, you do not melt the base metal. The high-temperature heat leads to a weld pool of molten material, which then cools to form a joint, which becomes stronger than the parent material.
At times, you can use the pressure to produce a weld and join the metals. Shielding can be used to protect the filler or melted metals from getting contaminated. Start here if you are interested in metal or welding art and master your welding skills by being consistent in your work.
Earlier, the wood used to be joined with adhesives or nails, but now you can easily weld the wooden materials utilizing the heat generated from their friction. It is done by subjecting the wooden pieces to a significant amount of pressure, and then linear friction is applied, which creates heat to weld the work pieces together.
Plastic welding is usually carried on compatible thermoplastics that need to be joined with a molecular bond. There are three major steps in the plastic welding process: pressing, heating, and cooling. First, the pressure is applied to the plastic, and then it is heated and joined to create a fusion. The welded part becomes strong when the heated joint starts coming back to a normal temperature.
Types of Common Joints:
- T Joint:
T welding joints are formed when two materials are joined with an intersection of 90 degrees. It can be seen as a connection between the endpoint of one material onto the face of another material. T joints are known to be a type of fillet weld and can also be created with a pipe or tube on a base plate.
- Butt Joint:
A butt joint is formed when two materials are joined through their ends or edges, making an angle of 135-180 degrees at the connection point.
- Edge Joint:
Edge joint is formed when two materials are joined through their edges with an angle of 0-30 degrees at the connection point. This joint is often applied to sheet metal parts that consist of flanging edges.
- Cruciform Joint:
A cruciform joint is formed when three metal plates are welded at right angles. It can also be seen as two metal bars welded to a flat plate on the same axis. These joints suffer fatigue if you put varying loads on them.
- Lap Joint:
A lap joint is formed when two materials are joined in an overlapping pattern and placed on one another. This joint can form an angle in the range of 0-5 degrees in the region of weld.
- Corner Joint:
A corner joint is formed when two materials join to form an angle in the range of 30-35 degrees in the joint region. In the corner joint, you need to weld on both sides to strengthen the bond.
Types of Welding Methods and Their Uses:
The arc welding method consists of various processes such as stick welding, metal inert gas (MIG) welding, tungsten inert gas (TIG) also called as gas tungsten arc welding, metal active gas (MAG) welding, flux cored arc welding (FCAW), gas metal arc welding (GMAW), shielded metal arc welding (SMAW), gas welding, and plasma arc welding. These processes can be manual, semi-automatic, or automatic.
They require a filler material and are used for joining metals like aluminium, nickel and copper alloys, stainless steel, cobalt, and titanium. They are used across various industries like automotive, oil and gas, aerospace, power, and many others.
- Electron Beam:
In this welding method, the materials are joined using the heat generated by a beam of high-velocity electrons. The electrons hit the materials, which converts their kinetic energy into thermal energy, heating the metals so that their corners are joined together to form a weld after solidification. This welding process is done in a vacuum chamber to prevent the beam’s dissipation.
The electron beam welding is used across various industries such as nuclear power, rail, automotive, etc., where there is a need to join thick sections of metal.
In resistance welding, the metals are joined by applying pressure and passing current for a considerable amount of time through the metal area that needs to be joined. There is no additional material required to create a bond in this process, which makes it cost-effective than others.
There are two types of resistance welding, namely resistance spot welding and resistance seam welding. In spot welding, the heat is delivered between two electrodes and applied to a small area as the materials are clamped together. In seam welding, the electrodes are replaced with rotating wheels, thereby delivering a continuous leak-free weld.
In the friction welding method, materials such as steel, aluminium, or wood are joined using mechanical friction. The friction generates heat and softens the materials, which help them to weld together as they cool down. This method doesn’t require filler metals, shielding gas, or flux.
In the laser welding method, a laser is used to provide concentrated heat to join thermoplastics or metal pieces. This heat is ideal for deep welds and barrow. This method is used in the automotive industry as it is perfect for high volume applications.
We hope that now you have got a detailed overview of what all things are included in welding.