LAS SMAW TECHNIQUES - Components and good welding procedures

Las SMAW commonly referred to as bar welding or electric welding, cannot be used by everyone, even if it looks simple. However, if you follow the procedure and the following method, hopefully, you can support those of you who want to learn to weld and want to become a professional welder.

In addition to this article, the components and all questions relating to SMAW welding are dealt with.
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SMAW welding technology represents the basic capital for the profession of the welder. Before you become an argon welder, SCAW welder (MIG), combination welder or underwater welder start with the first SMAW welder. There is, but that means welder "Karbitan", too bad if argon welder can't weld Stick / Smaw.

It is not easy to become a professional welder, both Smaw welder and Argon welder and others. In addition to your interests and talents, patience, learning from the elderly and constant efforts are required to achieve results according to the specified welding standards. Other factors are good relationships with the project environment and with experts.



Las SMAW (Shield Metal Arc Welding) is a welding process in which the base material or base metal and the electrodes (welding wire) is melted by heat. The heat is generated by an electrical ion jump that occurs between the cathode and the anode (the electrode tip and the surface of the plate to be welded). The heat generated by this jump of electrical ions can be 4,000 to 4,500 degrees Celsius.

The welding process takes place due to the contact between the electrode tip and the base material so that a short circuit occurs and the welder (welder) has to pull the electrode when a short circuit occurs to form an arc that is the jump of ions that cause heat, The heat melts the electrode and the base material so that the electrode liquid and the base material liquid fuse together and form a weld metal.

In order to produce a good and constant arc, the welder must maintain the distance between the tip of the electrode and the surface of the base material in order to remain the same. The best distance is the same as the diameter of the electrode used, for example, a welding wire (electrode) 3.2 mm, so that a good distance between the base material and the electrode tip is also about 3 mm.

TYPES OF WELDING POLARITY

The SMAW welding process divides the electrical power generated by the machine according to the type of current delivered into three machine types:
1. Motor with alternating current
2. Machines with direct current
3. Machines with a combination of direct current (DC) and alternating current (AC)

An AC motor with a transformer is sufficient.

In current machines (DC) that are equipped with components that convert the type of alternating current (AC) into direct current that is generated with an electrical generator. The electrical efficiency is 80-85%. In a combination of AC and DC machines equipped with transformers and rectifiers, this rectifier has a function of flattening the current.

When welding alternating current (alternating current), the voltage drop is not influenced by the cable length, it is not suitable for low currents, not all types of electrodes can be used. This current leads to coarse welding and is therefore not suitable for use.

While in the welding process Smaw direct current (direct current) the voltage drop is sensitive to the shortest possible cable length, can be used for small currents with small electrode diameters, all types of electrodes can be used, starting the arc is easier for small currents in particular, which is what the majority of the manufacturing industry uses DC polarity especially for Carbos steel.

Basically, the DC polarity in Smaw welding is divided into two parts, namely the DCEP polarity and the DCEN polarity

1. DCEP polarity (reverse polarity)

How it works The base material is connected to the minus pole (-) and the electrodes to the plus pole (+) of the DC welding machine, so that the arc travels from the base material to the electrode and 2/3 of the heat on the electrode and 1/3 of the heat on the electrode creates basic material.
This process leads to a stronger melting of the electrode so that the weld penetrates flat.

2. DCEN polarity (even polarity)

The basic principle of the base material or the material to be welded is connected to the positive pole (+) of the Travo, and the electrodes are connected to the negative pole (-) of the DC welding transformer.
In this way, the arc moves from the electrode to the base material, resulting in 2/3 of the heat in the base material and 1/3 of the heat in the electrode.
This process produces more base material melt than the electrodes so that the weld seam has a deep penetration. This polarity is generally used for welding TIG (gas-tungsten-arc welding).

 

LAS SMAW COMPONENTS

Devices that are required for the SMAW welding process are the simplest devices compared to other electrical welding processes. The rough welding machine is:
  1. DC / AC transformer
  2. Earth cable and electrode cable
  3. Brackets and earth clamps
  4. electrodes
  5. connections
  6. Chipping hammer
  7. Wire brush and suitable personal protective equipment.


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The following description of the components of Las SMAW

- a voltage source (current source)
Voltage sources are divided into AC welding machines and DC welding machines, AC welding machines are usually designed as welding transformers, and DC welding machines are equipped not only with transformers but also with rectifiers or diodes (alternating current to direct current), which usually drive both diesel motors by motor gasoline and electric motors. Direct current welding devices, currently widely used direct current welding devices, since the direct current has several advantages over the alternating current welding device, ie stable arc and polarity can be regulated. AC welding machine with a transformer or welding transformer.

- Ground cable and electrode cable (ground cable and electrode cable)
Ground cables and electrode cables conduct electricity from the welding machine to the weld metal and back to the welding machine. The earth cable and the electrode cable must be large enough to carry electrical current. If they are not large enough, the cable will be heated and the cable insulation will be damaged, which will ultimately endanger welding.

- Holder (electrode clamp) and complaint period
The electrode holder is useful for conducting electrical current from the electrode cable to the electrode and as an electrode holder so that the welder does not feel hot when welding. Ground clamps are useful for connecting the welding machine's cable ground to the material. As a rule, the earth clamp has a spring for the clamp. This clamp is very important because the current generated when the clamp is loose is not stable and the welding cannot proceed properly.

- electrodes
Most SMAW welding electrodes are coated with a flux layer that acts as a gas formation and protects metal liquids from contamination of the ambient air. In addition, fluke is also suitable for the formation of welding slag, which also serves to protect the welding fluid from the ambient air. This electrode layer is a chemical mixture, the composition of which corresponds to the welding requirements. According to the AWS (American Welding Society), electrodes are classified with the letter E and followed by four or five digits as follows: E XXXX (x), for example, E 6010, E 6013, E 7018 and others.
- welding hammer and wire brush (chisel hammer and wire brush)
The IAS hammer is used to remove and remove the welding crust on the IAS metal (weld metal) by hitting or scraping off the welding area. Carefully clean the Ias scale with a hammer, as it may splash into the eye or other parts of the body. Do not clean the welding crust when the welding scale is still hot/red.
The wire brush is used to: clean the workpiece to be welded and the welding slag released from the welding path by a welding hammer stamp.

SMAW WELDING POSITION




What do we mean by positions 1G, 2G, 3G, 5G or 6G on welding?
The connections on the base or the metallic material linked to welding have different types, ranging from blunt joints (butt joint), corner joints (T joint), corner joints (corner joint) or overlapping joints (lap joint).

These types of connections certainly have their own goals and objectives. This also concerns the welding position. This is why we know the different types of welding positions. For the plates, we recognize the welding positions 1F, 2F, 3F and 4F, there are also 1G, 2G, 3G and 4G. While the pipes are 1G, 2G, 5G and 6G.
The above connection types and welding positions can be applied for SMAW, GTAW, GMAW and FCAW welding.

For more details on the welding position, see the following image.

- The type of leave connection (T-joint) is 1F (flat), 2F, 3F, and 4F, as shown in the figure below:
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- The types of ordinary plate connections are positions 1G (flat), 2G, 3G and 4G:

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-The types of solder joints on the pipes are 1G, 2G, 5G, and 6G:

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The 1G connection type means that when welding, the position remains flat but the pipe is turned. In position 5G, the pipe is fixed but the welding position follows the pipe connection groove.
GOOD WELDING PROCEDURE
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To produce a quality welding smaw quality, there are 7 parameters to take into account, this tip is obtained from modern book welding technology, the following parameters:
1. Selection of the correct type of electrode from the tensile strength, the type of material and the type of coating to correspond/correspond to the material to be welded.

2. The choice of the diameter of the electrode used is considered according to the type of electrode, the welding position, the design of the joint, the thickness of the material and the skills of the welder.

3. Appropriate use of current
In smaw, the welding has a very strong influence on the welding results. If the current is too high, the electrodes will melt too quickly and will be difficult to control. If the current is too low, the welding results will accumulate and will be irregular.

4. Precise and constant arc length
In smaw welding, if the arc length is too long, a large globule will occur so there will be a lot of spatter when welding, and porosity may occur if the arc length is too short, this will cause excessive heat leading to deep penetration and may cause the base metal to burst (blowhole)).

5. Correct rotation speed
If the speed of movement is too high, the liquid metal will freeze quickly and the weld bead will be weak, dirt and gas will be trapped and may cause welding faults if the weld bead is too high and too wide and the welding results will be crumpled.

6. The correct welding angle
In smaw welds, the angles of the electrodes are very important, especially when welding threads and deep groove joints. if the welding angle is not correct, this can lead to an undercut, etc. generally the angle used is 70 to 80 degrees

7. Correct the oscillating electrode (welding manipulation).
Because each electrode has different oscillation characteristics from welding to welding manipulation depending on the type of electrode, the design of the connection, the welding position and the experience of the welder himself.

EXCESS AND LACK OF SMAW LAS

The advantages of SMAW welding:

1. Low initial investment costs
2. Operationally reliable and simple
3. Low filling cost
4. Metallic fillers/fillers may vary
5. Welding can be used in all materials
6. Can be made at any material thickness
7. SMAW welding is very suitable for use in field welding due to its great flexibility.

Disadvantages of SMAW welding:

1. Slow replacement of electrodes
2. There is a slag that must be removed
3. With low hydrogen content, the electrodes require special storage which must be heated before use
4. Low efficiency of sediments and sensitivity to welding defects, porosity and inclusion of slag.

So the publication on Las SMAW Technique can hopefully add knowledge and information about smaw welding.
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