Welding process is used to join the metals permanently. In the welding process we can join more than two metal pieces to act as a single section. In many countries mare than 50% of the industrial gross products are related to the welding process only.
There are various welding processes. Sometime the welding process produces sparks and some other does not require any external heat. Welding process can be done in all areas like outdoor, indoor, under water etc.
- Welding process is mainly used in the fabrication process like air crafts and space craft, rail coaches , building structures, pressure vessels and some general applications
- In air crafts for joining of the sheet to the body of the plain welding process is applied. In the space vehicle we can see outer part of the body is encountered with rapid heat and also low temperature requirement for the outer body.
- Welding is required in the automobile components like fuel tanks, chassis, door hinges etc.
- Welding process is commonly used in the transport tanks construction for the transportation of milk, oil, water and many other liquids, these are the general application of welding process
- In the process of ultrasonic, electron beam, micro plasma and laser; welding is used for the joining of foil to wire, foil to foil and wire to wire connections to create a junctions of strain gages, thermocouples to wire leads.
- In the manufacturing of the war equipment’s, in the defense industries welding process is used
Identification of methods used:
There are three types of welding process, they are vary with the cost and speed.
- Stick welding
- Semi-automatic welding
- Automatic welding
Stick welding is also done and seen in remote areas. For this welding it requires very minimum amount of equipment and it provides high flexibility. Within seconds it performs the operations like converting the mild steel into stainless once. For this type of process they required high skill labor.
In the semi-automatic welding process it requires fed electrodes and wire feeders. The operator should handle the welding gun. For continuous process the fed wire is inserted in the welding gun. Compare with the stick welding semi-automatic welding is easier to learn. In farm houses the semi- automatic welding becomes more popular process, as it increases the installation rates over manual welding. There is no requirement to stop the burning rod.
In automatic welding we need to provide high range of initial setup. It reduces high rate of deposition to obtain maximum productivity. The gun must be carried by an automatic moving operator. The operator will start the machine by click on the start button. Automatic welding equipment is found in farmhouse. In most cases we see the equipment in repair centers due to heavy size.
It consists of 5 factors they are
- Preheat treatment
- Correct procedure
- Proper cooling down
- Heat treatment
Before starting the welding process you need to clean the metal and then dry. Remove the dirt, grease, rust and other impurities by using the wire brushing. The pollutants present on the work piece causes cracking, porosity and poor welding quality. With the help of the grinding operation remove the impurities and cracks.
In many welding operating the work pieces are undergone for the preheat treatment or hard facing operation, because it contains carbon content, alloy content, part rigidity and massive size. To bring the work piece to the room temperature pre-heat treatment application is required. It maintains the temperature of 70 to 100 F. To prevent the metals( medium to high carbon alloys and low alloy steels) from cracking, stress failure, welding crack it require high pre-heat treatment. Special crayons are available to identify the proper preheat temperature.
In the initial step the process one needs to identify is the traveling speeds, amperage, polarity, size of welding and other things need to understand. The connectivity must be uniform, free from porosity, undercut and smooth.
Proper cooling down:
Pre heating is the actual way of limiting the Cooling rate of controlled parts or massive parts which are naturally sensitive. After welding process comes to an end is provides shielding to the work piece with the help of glass fiber, sand and lime. It helps to minimize the cooling stress, bend and cracking. Never use ice or water as a coolant as it leads to a weld cracking, internal stress etc.
Some cases heat treatment is required to warm up the material; in the process heat is provided to the work piece material and permits it for slow cooling.
- Place the welding equipment in the high ventilated area to send the harm full flames out-side
- During the process, proper safety materials are used to protect your hand, eyes and body etc.
- Do not touch the electrical parts during the process is in ‘ON’ state
- Try to avoid the process near the oil bunks, hydraulic fluids and diesel and in enclosed space.
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