1. GMAW SOLID AND METAL CORE ELECTRODES

2. Selecting the appropriate GMAW electrode for a particular welding job is an essential skilled for a well trained welder.
Like Shielded Metal Arc Welding electrodes, all electrodes used for the GMAW process have an AWS specification and classification number.
The AWS specification number for all GMAW solid and metal cored electrodes is AWS A.5.18.
The classification number for all of the electrodes contained in the AWS A.5.18 are as follows:
Solid Wire Electrodes
E R XX S- X HZ Example: ER70S-3 or E70S-6
E - Electrode (may be used as)
R – May be used as filler rod
XX - Minimum tensile strength of weld deposit X 1000PSI. (May consist of three digits)
S – Solid wire
X – Chemical composition and operating characteristics
HZ – optional supplemental hydrogen designator

3. Metal Cored Electrodes
E XX C – X Y HZ Example: ER70C or E70C-6MH8
E – Electrode (may be used as)
XX - Minimum tensile strength of weld deposit X 1000PSI. (May consist of three digits)
C – Composite metal cored electrode
X – Chemical composition and operating characteristics
Y – Shielding gas designator (“C” indicates CO2 and “M” indicates percent argon, balance CO2)
HZ – Optional supplemental hydrogen designator

4. Selecting GMAW Electrodes
When selecting a GMAW electrode for a given job, the following factors must be considered;
Type of base metal.
Match the electrode to the base metal as closely as possible.
Properties of the deposited weld metal.
Select the wire that matched the requirements for deposited weld metal.
Deoxidizing agents.
Deoxidizing agents are added to the electrode to prevent damage or porosity to the weld metal.
The most common deoxidizing agents are manganese, silicon and aluminum.
Arc type and desired metal transfer characteristics.
Match the type of electrode best suited to the type of welding being done.

5. Common Electrode Sizes and Weights
Common sizes for solid GMAW electrodes are:
.023
.025
.035
.045
1/16
3/32
1/8
Solid GMAW electrodes are available in the following weight spools or drums: 1 2 3 10 25 33
Also available are 300, 700 and 1,000 pound drums.