Aluminum welding technique with TIG welding machine

Aluminum welding technique with TIG welding machine

Date 06/05/2019

In aluminum welding, you have to understand the process of steps from causing the arc to the end of the arc. On the other hand, you should pay attention to the operation in the torch holder and adjust the metal rod at the appropriate angle.

Electrode:

 
In aluminum or Margie aluminum alloys, Tungsten electrode has round heads and pointed ends for welding carbon steel or stainless steel. After positioning electrodes, set welding electrodes in the welding torch, the excess electrode is about 3.2mm.
 

Selection for protection gases:

 
In aluminum welding, the most commonly used gas is argon with good cleaning and penetration properties. When welding aluminum alloys 5XXX - series, the protective gas is a gas mixture of argon and helium (no more than 75%) that minimizes the formation of magnesium oxide.

Arc manipulation:

 
Arcs can be generated by high voltage without contact between the electrodes and the welds when using high current AC or DC lines. As with hand-arc welding, arcs can form on their own before the desired arc length is achieved. Especially, arcs are near the starting point of the welding line until a molten metal pail appears at a certain size, which then moves the solder out of the weld.
 
In case of welding with DC currents (without high-rise building), it is necessary to touch the tip of the electrode in the welding material to create the arc. It should use tungsten-thorium electrodes. In order to limit the damage caused by arc welding, especially to welding aluminum, we should arc on a piece of copper metal.

Determination of arc length:

 
In welding Tig, the appropriate arc length for most metals is about 1.5 times as long as the diameter of the electrode. As a rule, the shorter the arc length, the more concentrated the heat of the conductor is, the narrower the width of the weld and the higher the penetration. As the length of the arc increases, the concentration of heat decreases, leading to a decrease in the amount of heat.

Arc switch operation:

When preparing the arc cut, the welding speed should be increased to limit cracking at the end of the weld. In addition, some welders have the habit of resurrecting the arc as soon as it is cut off for the purpose of melting the secondary metal to fill the dimple.

Selection of tilt angle torch:

 
Angle of 90 degrees tilting applies to termite joints. However, it is better to allow the specimen to be tilted at an angle of about 60 degrees from the transverse direction. The inclination of the secondary metal to the horizontal is less than 20 degrees.
 
The best angle of inclination of the torch is 45 degrees on either surface (ie, at the right angle of the right angle) for superimposed and superposed links. Tilt 5 to 15 degrees to the direction of welding.
 
In cases where the welds have different thicknesses, the weld point has a slight offset to the larger thickness in order to balance the melting point.
 
A rule in aluminum welding is to conduct "fast and hot". Compared with steel, the high aluminum conductivity required for welding, large welding voltages at faster torch migration speeds. Because of the slow moving of the torch, it is easy to burn, especially with thin parts.

Attention in the welding process:

 
Use zirconium-tungsten electrodes 2.4mm diameter for beginners. Air flow protection of about 15cfh, current intensity of 165A.
 
Place the torch on the aluminum plate, the electrode posture is ready to move, the angle of inclination to the horizontal surface is about 20 degrees.
 
If we want to fill the secondary metal into the weld, we first have to create a molten puddle of metal, at the beginning of the weld, until the proper setting is achieved. Then move the arc back to the welding puddle. Once the arc has left, begin dipping the tip of the secondary metal rod into the molten metal.
 
One of the newcomers mistakes is to use an arc to directly melt the secondary metal rod. This results in the formation of metal clumps in front of the welding puddle. It is only possible to melt the secondary metal rod by immersing it in a molten metal, whereby the molten metal from the metal rod is sufficient to fill the weld pile for fine welds.
 
When the weld has reached the required size, proceed with the removal of the welding rod, moving the welding torch forward to melt the metallic component next to it, along the welding line.
 
The procedure is repeated to weld the full length of the weld. Disconnect the arc and turn off the appliance after the end of the weld.
 
Before welding the joints, it is important to practice welding  well.

Warning before welding:

 
Preparing the solder: The cleaning of the solder surface is essential, especially for aluminum welding. Use a brush to clean the aluminum oxide layer and grease on the surface of the weld. It is extremely important to clean the aluminum oxide layer on the surface(to limit the penetration of the solder filler) by melting it up to 3700 degrees Fahrenheit while the aluminum metal is only 1200 degrees F.
 
Stainless steel brushes can be used to clean the aluminum oxide layer on the solder surface or other corrosive methods.  when using a brush, do not brush too hard,which will increase the roughness of the solder and increases the risk of ingestion of oxide. Separated brushes should be used for cleaning aluminum welds, avoiding the need to clean the welds of steel or other stainless steel.
 
In the case of chemical cleaning, you must ensure that the solvent must be cleaned with a detergent prior to welding. Make sure the bleach does not contain the hidrocacbon component.
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