7.13 GMAW and FCAW Electrode Wire
Bare metal electrodes used for gas metal arc welding are small in diameter. Diameters range from 0.020″ to 0.125″ (0.5mm to 3.2mm). The most common diameters are 0.030″, 0.035″, and 0.045″ (0.8m, 0.9mm, and 1.1mm). Electrode wire is sold in spools of several hundred feet or meters, or in drums containing up to several thousand feet or meters of wire coiled inside.
7.13.1 GMAW Electrode Wire
GMAW electrode wire is a continuous solid electrode wire. It is wound onto spools or packaged in drums. Spools can be as small as a 1 pound (0.45kg) spool. A very common spool size for manual GMAW is a 44 pound (20kg) spool. Electrode wire sold for automated welding can be packaged in 500 pound (227kg) drums or in 1000 pound (454kg) reels.
GMAW electrode wire is manufactured to confirm to specifications of the American Welding Society. A variety of wire compositions are available for use as GMAW electrodes. Figure 7-27 lists the AWS specifications that should be referred to when selecting electrodes for use with different base metals.
Deoxidizers and denitrifiers are elements added to most electrode wires to reduce the porosity in the finished weld. During the welding process, the deoxidizers and denitrifiers added to the wire will combine with and work to remove any oxygen, nitrogen, or hydrogen from the weld. Deoxidizers reduce the possibility of these gases reacting with the molten weld metal or from producing porosity, which would lower the mechanical strength of the weld.
The American Welding Society chemical composition specifications for carbon steel filler metal used with GMAW are shown in Figure 7-56. Figure 7-57 lists the AWS filler wire specifications for GMAW low-alloy steels.
The numbers and letters used in the AWS classifications in Figures 7-56 and 7-57 have the following meanings:
Bare metal electrodes used for gas metal arc welding are small in diameter. Diameters range from 0.020″ to 0.125″ (0.5mm to 3.2mm). The most common diameters are 0.030″, 0.035″, and 0.045″ (0.8m, 0.9mm, and 1.1mm). Electrode wire is sold in spools of several hundred feet or meters, or in drums containing up to several thousand feet or meters of wire coiled inside.
7.13.1 GMAW Electrode Wire
GMAW electrode wire is a continuous solid electrode wire. It is wound onto spools or packaged in drums. Spools can be as small as a 1 pound (0.45kg) spool. A very common spool size for manual GMAW is a 44 pound (20kg) spool. Electrode wire sold for automated welding can be packaged in 500 pound (227kg) drums or in 1000 pound (454kg) reels.
GMAW electrode wire is manufactured to confirm to specifications of the American Welding Society. A variety of wire compositions are available for use as GMAW electrodes. Figure 7-27 lists the AWS specifications that should be referred to when selecting electrodes for use with different base metals.
Deoxidizers and denitrifiers are elements added to most electrode wires to reduce the porosity in the finished weld. During the welding process, the deoxidizers and denitrifiers added to the wire will combine with and work to remove any oxygen, nitrogen, or hydrogen from the weld. Deoxidizers reduce the possibility of these gases reacting with the molten weld metal or from producing porosity, which would lower the mechanical strength of the weld.
The American Welding Society chemical composition specifications for carbon steel filler metal used with GMAW are shown in Figure 7-56. Figure 7-57 lists the AWS filler wire specifications for GMAW low-alloy steels.
The numbers and letters used in the AWS classifications in Figures 7-56 and 7-57 have the following meanings:
- Example: ER70S-2
- E—electrode
- R—rod
- 70—tensile strength in ksi (1000 psi)
- S—solid rod
- 2—variations in chemical compositions
- Examples of dash numbers:
- B2—chrome-molybdenum steel
- B3L—chrome-molybdenum steel with a lower carbon content
- Ni (1-3)—nickel steel
- D2—manganese-molybdenum steel
Figure 7-56. AWS A5.18/A5.18M:2005, Table 1, Chemical Composition for Carbon Steel Filler Metal Used with GMAW, reproduced with permission from the American Welding Society, Miami, Fl. For exact limitations and more information, see AWS specification A5.18.