Electric arc welding or commonly referred to as electric welding is a process of joining metals including using electricity as a heat source. This type of connection with welding Iistrik is a fixed connection. There are several kinds of processes that can be classified kadalam Iistrik Ias process were:
1. Las Electricity with Carbon Electrodes, for example:
Electric welding with a single carbon electrode.
Electric welding with double carbon electrodes.
2. Las Electricity With Metal Electrodes, example:
Electric welding with electrodes webbed
Las iistrik TIG (Tungsten Inert Gas)
Las Iiarik submerged
Principles Las Electricity
Basically electric welding using carbon electrodes and metal using electricity as a heat source. Electric arc that occurs between the tip of the electrode and the workpiece can mancapai high temperatures that can melt some of the material is obtained by multiplying the voltage (E) a powerful invitation current (I) and time (t) are expressed delam units, heat joules or calories as the formula below this:
H = E x I x t
H = hot in units of joules
E = delam volt power supply voltage
I = current in amperes strong
t = time in seconds
1. Las Electricity With Carbon Electrodes (Arc Welding)
Electric arc that occurs between the end of the carbon electrodes and metal or between two carbon electrode tip will heat up and melt the metal to be welded. As an added ingredient can be used electrodes with a flux or flux-covered electrode.
Las tistrik uses webbed alektroda as added ingredients. Electric arc that occurs between the electrode tip and the base material will melt the electrode tip and some basic ingredients. Membrane electrodes are also burning will melt and produce gas that protects the ends of the electrodes, the crater Ias, bow Iistri and Ias area around the arc to the influence of the outside air. Liquid membrane electrode surface Ias freeze would cover that also serves as a protection against external influences.
Img. Below is an electrical circuit with the electrode webbed Ias where G is a direct current power source and an electrode connected to the terminal negetif being material to the positive terminal.
|Electrical Circuits Welding|
|The transfer of liquid metal from the electrodes to the Base Metal|
As an added ingredient used without membrane electrode is moved and brought to lirtrik arc occurring between the tungsten electrode with the base material.
As used protective gas argon, helium ateau mixture of two gases which pemekaiannya tergsntung of types logem be welded.
Stalk TIG welding is usually cooled by circulating water. Electric Ias TIG process is shown in Fig below
Submerged electric welding is generally automatism or semi-automatic use of flux powder to the protective effect of the outside air. Electric arc between the electrode tip and the base material is in flux pile of powder so it does not happen beam welding out separti usually on other electrical Ias. In this case the operator does not need to use glass Ias eye protection (helmet Ias).
At the time of welding, flux powder will melt and freeze shut Iapisan Ias. Most of the flux powder that does not melt can be used again after cleaning of slag slag Ias.
Electrode which is shaped coil wire without membrane (roller) is driven forward by a couple of gears. couples gear rotated by an electric motor speed can be adjusted according to the welding needs.
Position weld consists of four kinds:
1. Position Hands Down
The position under the hand that is a way of welding is done on a flat surface / flat and made under the hand. The slope of the welding electrodes around 10º - 20º and 70º vertical terhada - 80º towards the workpiece.
2. Upright Position (Vertical)
Weld the upright position is if done welding direction up or down. This welding including welding of the most difficult because the liquid material flowing or diarah accumulate under the electrode can be minimized with a slope of about 10º - 15º and 70º vertical terhada - 85º towards the workpiece.
3. Flat Position (Horizontal)
Horizontal weld to weld also called uniform which made the upright position of the workpiece and the electrode to follow a horizontal direction. When welding electrodes made tilted about 5º - 10º and 70º vertical terhada - 80º towards the workpiece.
4. Position at Top of the Head (Over Head)
Welding position is very difficult and dangerous because many liquid material can fall on the welder, therefore, necessary equipment Self-contained, among others: Wear welding gloves, leather shoes and so on. Weld with the position of the workpiece is located on the top of the welder and electrode position around 5º - 20º and 75º vertical terhada - 85º towards the workpiece
Types of welding defects
1. Porosity, this defect is a defect that is due to the gas trapped in the weld area in excess of the boundary conditions.
These defects can be caused by several things, among others:
- Excessive amps / volts
- Excessive travel speed
- Incorrect electrode angle
- excessive weaving
- Incorrect welding technique
- Electrode too large
This defect due to:
- Flow is too low
- Low welding speed
- Error welding techniques
- contamination around
Many things can cause this defect. examples of crack are as follows:
|Type of discontinuity|