GMAW (MIG Welding) electrode specification

GMAW (MIG welding) electrodes are designated by some letters and numbers such as ER70S-6, ER90S-6 and E308L etc. I will explain the meaning of these symbols:

FOR CARBON STEEL OR MILD STEEL (SUCH AS ER70S-6 OR ER70S-3)

Where,

ER – Designates electrode or filler rod

XX – Designates the minimum tensile strength of the deposited weld metal

S – Stands for solid wire

Y – Designates the chemical composition of the additives such as deoxidizing agent or cleansing agent used on the electrode, it may affect the polarity setting also.

FOR EXAMPLE:

ER70S-6

Where,

ER – Designates a welding electrode or filler wire

70 – Designates the minimum tensile strength of the deposited weld metal shall be 70 Ksi or 70,000 Psi

S – Stands for solid wire

6 – Reflects the amount of oxidizing agent and cleansing agent on the electrode. In particular the number 6 means that more deoxidizers have been added to the wire, which is helpful when welding on dirty or rusty steel.

 

FOR STAINLESS STEEL

Stainless steel electrodes are designated in a slight different way. Some of the commonly used stainless steel electrodes are ER308L and ER309L etc. Meaning of these symbols is explained below;

ER308L

Where;

ER – Stands for electrode or filler wire

308 – Designates the grade of stainless steel of the electrode or filler wire

L – Designates that it is a low carbon electrode

 

FOR ALUMINIUM

For Aluminum, electrodes are designated as ER4043, ER5350 etc. These electrodes are designated in a different way. For example;

ER4043

Where,

ER – Stands for electrode or filler wire

4 – Designates series of Aluminum of which the electrode is made from. In this case it’s a 4000 series Aluminum

043 – Reflects the amount of silicone added to the electrode

 

SHIELDING GAS:

GMAW requires a shielding gas, to protest the weld pool from atmospheric contamination. We use Inert gases as Shielding gas for MIG welding these gases are as below:

  • Argon
  • Carbon Dioxide
  • Helium

These gases are used alone or a combination of gases can also be used. Commonly used combinations of inert gases are;

  • 75% Argon + 25% Carbon Dioxide (most popular combination)
  • 98% Argon + 2% Carbon Dioxide

Argon helps in achieving cleaner weld whereas, Carbon dioxide helps in getting a deeper penetration. Carbon dioxide can be used alone also and it is effective while welding thinner metals.

 

6 comments

  1. In the case of aluminium filler material also, last three digits are specifying the chemical composition or grade only, not just the amount of silicon. Anyway, the blog is very informative. Go ahead.

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