Guides of TIG welding

Guides of TIG welding

Date 06/05/2019

What is TIG welding?

TIG welding (Tungsten Inert Gas) is a method of arc welding in a protected gaseous atmosphere with a non-melting electrode (TIG) generated by an arcing rod and maintained between a non-melting electrode Tungsten and weld surface. The heat-affected area, the welding pool, and the Vonfram are covered and protected by an inert gas. Inert gas (such as Ar, He ...) does not chemically react with molten, non-flammable, colorless, odorless and transparent metals, which allows welders to clearly observe the welding process. It is possible to add a little amount of other gases into this process,such as hydrogen to increase the welding velocity.
 

Types of welds in TIG welding

Types of welds in TIG welding

Preparation of the weld bead:

Preparation of the weld bead

TIG Welding Guides

The arc length, the gas cup size, the output electrode (welding needle)
 
The arc length is equal to the diameter of the electrode or equal to the diameter of the electrode tip when it is rounded.
 
TIG Welding Guides
 
The inner diameter of the gas cup must be at least three times the electrode diameter to provide sufficient gas to protect the weld. For example, when using an electrode diameter of 1.6mm, a minimum of 4.8mm gas should be used.
 
TIG Welding Guides
 
Figure: Location of the torch and relative size between the electrode and the internal diameter of the gas capture.
 
1. Welding materials; 2. mass clamp; 3. Welding; 4. Sub-welding electrodes; 5. gas capture; 6. Electrodes
 
The length of the tungsten electrode's output is at least equal to the electrode diameter. As usual, the length of the tungsten electrode is about 5mm. Electrodes coming out of the gas capture will increase the risk of sticking to the electrode with an auxiliary welding rod or electrode dipped into the welding puddle.
 
The location of gas capture when induced by high frequency arc
 
TIG Welding Guides
 

TIG welding technology:

 
 
When the arc appears, the flow is fixed until the lump is formed. The welding torch is tilted at an angle of 75 degrees in horizontal direction and moved at a stable speed.
 
Note: The ends of the red hot cathode and the welding pool must be covered with protective gas.
 
The welding rod is held at a 15 degree angle to the weld
 
TIG Welding Guides
 
Pipe welding technique
 

TIG Welding Guides

The electrodes used for tube welding are tungsten electrode with 1.5% lanthanum or 2% thorium (red).
 
Select a second welding rod is bigger than the welding edge gap.
 
Welding Materials:
 
When welds are less than 1.6mm thick, we do not need auxiliary welding rods because the metal at the weld edge can be melt and mix together.
 
When welds thicker than 1.6mm, we need to use additional welding rods to supplement the weld metal. Metal supplementation with an auxiliary welding rod will be carried out manually . The diameter of the auxilary welding rods should be equal to the electrode (welding needle).
 
Additional welding rod diameter: 1.6, 2.4, 3.2, 4.0, 4.8, 6.4.
 
Length about 900 ± 20mm (for steel rod, 450 ± 12 (for cast iron rod)
 
Steel welding rod 
 
Symbol: ER 70 - S6
 

ER - Electrode Rod: Can be used for both TIG and MIG / MAG, if R is not used then this material is only for MIG / MAG.

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