Lanthanated Tungsten Electrodes
Lanthanated (1% Lanthanum, Black), (1.5% Lanthanum, Gold),
(2% Lanthanum, Blue) AWS A5.12 EWLa-, ISO 6848 WL
These TIG electrodes are alloyed with non-radioactive lanthanum oxide, often referred to as lanthanum, another of the rare earth elements. These electrodes have excellent arc starting, low erosion rate, arc stability and excellent re-ignition characteristics.
The addition of 1 – 2% lanthanum increases the maximum current carrying capacity by approximately 50% for a given size electrode using alternating current compared to pure tungsten. The higher the percentage of lanthanum, the more expensive the electrode. Since lanthanum electrodes can operate at slightly different arc voltages than thoriated or ceriated tungsten electrodes, these slight changes may require welding parameters and procedures to be adjusted.
The 1.5% content appears to most closely match the conductivity properties of 2% thoriated tungsten. Compared to cerium and thorium, the lanthanum electrodes have less tip wear at given current levels. Lanthanum electrodes generally have longer life and provide greater resistance to tungsten contamination of the weld.
Parameters of Lanthanated Tungsten Electrode
|
Type |
Additives |
Content |
w% |
Sing Color |
|
WL10 |
LaO2 |
0.80~1.20% |
＞98.4 |
Black |
|
WL15 |
LaO2 |
1.30~1.70% |
＞97.5 |
Golden Yellow |
|
WL20 |
LaO2 |
1.80~2.20% |
＞96.5 |
Sky Blue |
Tolerances of this Lanthanated Tungsten Electrode
|
Diameter (mm) |
Tolerance (mm) |
Length (mm) |
|
Φ1.0-Φ2.4 |
±0.05 |
50~175 ±1 |
|
Φ3.0-Φ12.0 |
±0.1 |
The lanthanum is dispersed evenly throughout the entire length of the electrode and it maintains a sharpened point well, which is an advantage for welding steel and stainless steel on DC or the AC from advanced squarewave power sources. Thus, the lanthanum electrodes work well on AC or DC electrode negative with a pointed end or they can be balled for use with AC sine wave power sources.
