welding noun /ˈwel.dɪŋ/ n [U] the activity of joining metal parts together
(Definition of welding noun from the Cambridge Advanced Learner’s Dictionary)

Welding in industry has huge spectrum! it starts for arc welding, to fusion welding, to Laser and so on and so forth,

Generally, pressure vessel speaking, we use following three type of welding

– SMAW : Shielded Metal Arc Welding
– SAW : Submerged arc welding
– TIG : Tungsten Inert Gas welding
– GMAW : Gas Metal Arc Welding

Other types are
-Atomic Hydrogen Welding(AHW)

-Bare Metal ArcWelding(BMAW)
-Carbon ArcWelding(CAW)
-Electro Gas Welding(EGW)
-Electro Slag Welding(ESW)
-Plasma Arc Welding(PAW)
-Stud Arc Welding(SW)

Lets discuss Generall Welding Process in Brief

As you can see in picture, the arc is created between Parent material and electrode. The oxidation is avoided by the flux coated on electrode. Due to arc the weld metal start melting, and due to high temperature, the flux also get melted, due to density difference, the flux floats over weld pool, and thus by function makes a barrier between atmosphere & weld to avoid any oxidation.
The temperature found in arc is as high as 7000ºC, at which the gas/air get ionized, providing good electrical conductivity in the arc.
The actual transfer of metal from the electrode to the workpiece is in the form of molten globules of different sizes depending on the type of electrode used. Some electrodes produce globules that are so large that they actually shortcircuit the arc for a moment.
Electrodes for manual arc welding (sometimes referred to as stick welding) consist of a rod and a coating material. As a rule, the alloy in the rod will be similar to the material to be welded.

The most common types of electrodes are:
1. The Organic type (electrodes contain large quantities of organic substances such as cellulose)
2. The Rutile type (electrodes contain large quantities of the mineral rutile)
3. The Acid type (electrodes produce an Iron Oxide / Manganese Oxide / Silica type of slag, the metallurgical character which is an acid.)
4. The Basic type (Low Hydrogen)
5. LMA (Low moisture absorption electrode)

TIG Welding:

In Tungsten Inert Gas welding (TIG), an arc is struck between a Tungsten electrode and the workpiece. An inert gas flow (Argon) protects the electrode and pool from the surrounding air. The electrodes do not melt.The filler metal is inserted into the molten pool in the form of a separate rod. The process has a similar welding technique as gas welding but use electricity as energy source.
GMAW / FCAW Welding
In Wire welding an arc is struck between a continuously fed wire and the workpiece. An inert gas, active gas or a mixture of the two protects the pool from the surrounding air. The wire used can be solid or flux cored. In some cases the flux cored wire is self shielded and does not require any additional shielding gas.
What are not covered? Gas Welding (Oxy-acetelene) and Brazing!
Hope this will give you sufficient over view.

Comments (1)

  1. SEO


    Thanks for the great details about welding, i really appreciate your research & knowledge in this domain.

    We are leading stainless steel welding company engaged in MIG Welding, TIG Welding, Stainless Steel Welding.

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