Choice of Gases and selections for MIG Welding for various Metals.

MIG welding machine supplier in India advice gases used in MIG welding process depending upon the metal to be welded in industries. Gas is what makes the MIG welding possible only. This is called as Metal Inert Gas Welding. The inert gases used in MIG welding are Argon and Helium as they do not react to anything unlike inert gases like O2 that will cause the metal to rust in. The gases shield the weld pool from the air, that may cause welding defects such as porosity. When CO2 & O2 are added to the mixture, then MIG welding is not technically MIG welding as these gases are no more inert gases. The process now becomes Gas Metal Arc Welding or GMAW.

Characteristics of MIG welding: The different gases suggested by MIG welding machine supplier produce different penetration and arc penetration as a general consideration.
. Argon gas has a shallow wide penetration and smooth arc like fluid.
. Helium produces a very hot weld with good weld productivity and a mild penetration with a fluid arc.
. Carbon Dioxide produces a deep and narrow penetration with a stiff and harsh welding arc that works well in out of
  position welding.
. O2 added to Helium or Argon in small amount deepens the weld penetration and stiffen the arc characteristics.
. CO2 added to Helium or Argon deepens penetration and stiffen the arc improving out of position welding.
. Helium addition or any mix may make the Arc hotter.
How Mig Welding Gas Effects Arc Transfer Type: The weld transfer type requires shielding gases.
  Following are the basics of transfer types related to gasses.
. Short circuit transfer needs pure CO2 or a high percentage of CO2.

. Globular transfer produces the best result with 75% or more Argon gas in a mixture.

. Spray transfer needs 75% Argon in pure depending on the material.

MIG Weld and Common Gasses Used: The following are the most common gasses used herein by MIG   welding machine supplier.
. Argon
. Carbon Dioxide
. Oxygen.
. Helium the least common.

 These gasses are used in mixture form in most of the situations. Oxygen is what causes most defects while in small percentage mixed with other gases it improves the arc characteristics. Argon and Carbon Dioxide can be used by themselves. In some cases, there is tri-mix shielding gas containing Argon, Carbon Dioxide, Oxygen, and Helium.

Basic guidelines for choosing the proper gases :
MIG Welding for Carbon Steel Welding- The welding in carbon steel can be done with Carbon Dioxide alone and it produces the deepest penetration, smoke, and rough welding. The most widely used mixture is called C25 and that is 25% Carbon Dioxide and 75% Argon gas. There are other mixtures that work well as designed by welding gas supply stores and chains. The commonest combination is a mixture of Argon, Carbon Dioxide and Oxygen.
MIG Welding Gas for Stainless Steel Welding- The welding of stainless steel is typically done with C2 or 2% Carbon Dioxide and 98% Argon. The Tri-mix shielding gas containing 90% Helium, 7.5%Argon, and 2.5%Carbon Dioxide. There are different combination suggested by a different gas supplier.
MIG Welding Gas for Aluminum Welding- The welding of Aluminium is typically done with Argon alone. If the Aluminium being welded is thicker than 1/2 of an inch then Helium may be added to the mix.

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