Before delving into the science behind welding it should be understood that there is a variety of types of welding. All of these can be utilized to join materials together. Hereunder, we are going to be discussing about the welding of metal as well as steel.
The most typical types of welding include:
- Wire feed welding - which is also known as mig, mag, gasless or flux cored.
- Arc welding - aka stick welding
- TIG (Tungsten Inert Gas) welding
- Gas welding
- Spot welding
Wire feed welding is also known as MIG welding. The proper term is GMAW or Gas Metal Arc Welding. When utilizing this welding method you have to hold a torch or gun in your hand and pull a trigger. Once you pull the trigger, wire within the torch is going to begin to come out. This wire is then pointed at what you wish to weld.
The technical term for arc welding is SMAW or MMAW. This refers to Shielded or Manual Metal Arc Welding.
Arc welding is a widely utilized technique of joining metal parts together. In this type of welding, the source of heat is an electric arc. An arc is made between an anode (positive pole of direct current power supply) and the cathode (negative pole). Arc welding is performed by making an arc between the work to be welded and the tip of the electrode. This form of welding has the benefits of less heat loss and less oxidation in comparison to oxyacetylene flame. An electric arc is an electric discharge in gases, occurring with high heat and a bright glow.
Whenever two conductors of an electric current are brought together make electrical contact, and then moved apart, an electric arc is made. A significant amount of resistance to the flow of the current is thus instituted, the electrode tips are elevated to high temperature caused by air gap between them.
The electrons which come out from the negative electrode come into contact with the molecules and atoms of air, break them up into ions and free electrons and make the air gap to turn into a conductor of electricity due to ionization. This sustains the current through the air gap and maintains the arc.
TIG (Tungsten Inert Gas) welding is a really fine and delicate welding skill. For this you have to hold your torch in one hand and utilize a filler rod in the other. The idea behind this form of welding is that you slowly feed the filler rod into the weld as you go along. You could weld with TIG or GTAW, Gas Tungsten Arc Welding
without utilizing the filler rod and only melt the two bits of metal together. This is called "fusing", where the usage of heat from the arc you melt and fuse it together.
In gas welding, gas flame is utilized for heating and melting the joining surfaces and the filler rod. Gas welding is the burning of a combustible gas with air or oxygen in an intensive flame of high temperature.
The most important combustible gas that gives the highest temperature is acetylene. Hydrogen is also utilized in gas welding of low melting point metals like aluminum. The temperature of oxyacetylene flame is around 3200 degrees Celsius and is enough to weld the steel. Acetylene is a compound of carbon and hydrogen (C2H2) consisting of 92.3% carbon and 7.7% hydrogen by weight. It is colourless and has a sweet and famed smell, whereas oxygen is a colourless, odourless and tasteless gas. The usage of pure oxygen speeds up reactions and elevates flame temperature. The reaction of oxygen with organic materials produces large quantities of heat.
The final form of welding that you have is known as "spot welding". This is frequently utilized for sheet metal fabrications. In brief, the two pieces of metal that must be joined together are put between the electrodes on the ends of the arms of the unit. They are brought together and the welded part is in between those points. It typically takes a second or so for this to occur. Just a simple buzz and that's it. This is a very quick means of joining sheet metal parts. Things such as toolboxes are a great example of what could be spot-welded.
There also exists a lot of other forms of welding processes for metal such as friction, ultrasonic, thermite and sub arc welding just to name a few. However, the ones mentioned above are by far the most commonly used forms of welding nowadays.
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