# Lanthanated tungsten electrodes

Lanthanum-oxide-doped GTAW electrodes: classifications, power-source selection, preparation, contamination and grinding controls.

Reviewed: 2026-11-01

Tags: consumables, welding, electrodes

Midwest Tungsten's published **blue 2% lanthanated** certificate lists **1/16 and 3/32 in** electrodes at **1.50 in length** with a **20° angle at both ends**. This is a product geometry. Match tip preparation, diameter and waveform to the issued procedure, and check actual lot documentation. [Midwest Tungsten Service, *2% Lanthanated Material Certification*](https://www.tungsten.com/asset/61bbc366adb27)

## Identity and classification

Lanthanum oxide is added to the electrode material. In GTAW the electrode carries the arc, with filler supplied separately when required. CK distinguishes the following grades:

| Nominal type | Principal lanthanum-oxide range | AWS designation | ISO designation | Tip marking |
|---|---:|---|---|---|
| 1.5% lanthanated | 1.3–1.7% | EWLa-1.5 | WL15 | Gold |
| 2% lanthanated | 1.8–2.2% | EWLa-2 | WL20 | Blue |

The nominal percentage is therefore a grade description, not an exact analysis for every rod. CK associates its designation table with AWS A5.12 and ISO 6848. Use the required standard edition and actual supplier documentation when ordering rather than treating this table as the complete standard. [CK Worldwide, *Tungsten Electrodes*](https://www.ck-worldwide.com/elektroden-aus-wolfram.html).

Preserve classification and package identity through cutting and preparation. A color band is useful identification, but it does not establish the diameter, preparation, delivered analysis or suitability for a welding procedure. Different oxide additions should remain identifiable even after the marked end has been shortened.

## AC, DC and equipment context

CK describes its 1.5% lanthanated product primarily for DC work on constant-current inverter or transformer power sources, including stainless, titanium, nickel and copper alloys. Its 2% lanthanated description covers both AC and DC and a broader general-purpose role. These are manufacturer selection descriptions, not universal amperage ratings or qualification for every alloy in those families. [CK Worldwide, *Tungsten Specifications*](https://www.ckworldwide.com/products/tungsten-specification).

Miller's guidance for advanced AC inverters includes both 1.5% and 2% lanthanated among recommended rare-earth options. It explains that balance controls influence cleaning action and electrode heat/geometry, while AC frequency influences arc shape. Consequently, a historical pure-tungsten recommendation or a table for another power source should not automatically govern a modern inverter setup. Match electrode selection to polarity, waveform and the issued welding procedure. [Miller, *How to Choose the Best Tungsten for AC TIG Welding*, 26 April 2026](https://www.millerwelds.com/en-us/resources/knowledge-hub/tig-welding/filler-metal-equipment-setup/how-to-choose-the-best-tungsten-for-AC-tig-welding).

Diamond Ground describes its blue 2% lanthanated product for heavy or pulsing amperage loads and resistance to thermal shock. Its page supplies several diameters in 7-inch stock lengths. Those descriptions support considering the product for such service; they do not establish a guaranteed electrode life, permissible current for every diameter, or equivalence to another manufacturer's grade. [Diamond Ground Products, *2% Lanthanated (Blue)*](https://diamondground.com/shop/2-lanthanated-blue/).

## Bounded dimensional examples

The blue 2% certificate lists 7-inch stock in 0.040-, 1/16-, 3/32- and 1/8-inch diameters, in addition to the short double-ended preparation. [Midwest Tungsten Service, *2% Lanthanated Material Certification*](https://www.tungsten.com/asset/61bbc366adb27)

The separate gold 1.5% certificate lists 7-inch electrodes in 1/16-, 3/32- and 1/8-inch diameters. Both certificates reference ISO 6848 and AWS A5.12 editions identified as 2009 and 1998, but show no visible issue date or lot identifier. They describe published product examples; verify the actual delivery documentation when a procedure requires a particular certification or edition. [Midwest Tungsten Service, *1.5% Lanthanated Material Certification*](https://www.tungsten.com/asset/61bbc3997636c), [Midwest Tungsten Service, *2% Lanthanated Material Certification*](https://www.tungsten.com/asset/61bbc366adb27).

## Diameter and preparation

Diameter affects starting behavior as well as current capacity. Miller advises larger diameters for higher amperage and smaller diameters for easier very-low-current starts. Select from the actual machine and electrode instructions; neither the blue marking nor a 2% label defines one universal current window. The electrode must also fit the torch's holding components and available length. [Miller, *All About Tungsten in TIG Welding: Types, Selection and Use*, 11 March 2026](https://www.millerwelds.com/en-US/resources/knowledge-hub/tig-welding/filler-metal-equipment-setup/all-about-tungsten-in-tig-welding-types-selection-and-use).

For modern inverter AC, Miller recommends a **truncated point**, rather than a needle point, to tolerate heat and reduce tungsten contamination. It distinguishes this from the traditional balled pure-tungsten preparation. Apply that recommendation in its equipment context; do not deliberately ball every lanthanated rod or copy a point angle without considering the procedure. [Miller, *How to Choose the Best Tungsten for AC TIG Welding*](https://www.millerwelds.com/en-us/resources/knowledge-hub/tig-welding/filler-metal-equipment-setup/how-to-choose-the-best-tungsten-for-AC-tig-welding).

Grind on a tungsten-dedicated abrasive and keep grinding marks parallel to the electrode axis. Miller warns that angled or spiral scratches can produce an unstable arc and that snapping or bending a rod to shorten it can introduce microcracks. Preparation errors can therefore imitate a material-selection problem. [Miller, *All About Tungsten in TIG Welding*](https://www.millerwelds.com/en-US/resources/knowledge-hub/tig-welding/filler-metal-equipment-setup/all-about-tungsten-in-tig-welding-types-selection-and-use).

Use the grinder's specified holding and minimum-length provisions. For example, Diamond Ground's **Piranha II DGP-PG2-A** manual lists included holding sizes of 1.0, 1.6 and 2.4 mm, minimum electrode length **44.5 mm**, and adjustments for included angle and tip flat. These are grinder capacities, not welding parameters. Its checked footer identifies **released May 2019, revision J**. [Diamond Ground Products, *DGP-PG2-A-V2 User Manual*](https://diamondground.com/wp-content/uploads/2019/05/DGP-PG2-A-V2-2019-Rev.-J.pdf).

## Contamination and service behavior

Contact with the molten pool, filler wire touching the hot electrode and base-metal impurities can contaminate tungsten. Miller recommends replacing contaminated electrodes to restore a clean arc. Keep prepared replacements available; an erratic arc after a dip does not by itself show that the lanthanum percentage is wrong. [Miller, *All About Tungsten in TIG Welding*](https://www.millerwelds.com/en-US/resources/knowledge-hub/tig-welding/filler-metal-equipment-setup/all-about-tungsten-in-tig-welding-types-selection-and-use).

Shielding remains important even with a stable electrode material. Miller's TIG gas guidance explains that inadequate coverage can contaminate both the pool and tungsten. It also notes that post-flow protects the electrode while cooling and that excessive flow can create turbulence and draw atmosphere into the shielding column. Check torch assembly, shielding delivery and procedure timing before attributing poor starts or rapid deterioration solely to electrode chemistry. [Miller, *Best Practices for Proper Shielding Gas in TIG Welding*, 11 March 2026](https://www.millerwelds.com/en-us/resources/knowledge-hub/tig-welding/how-to/best-practices-for-proper-shielding-gas-in-tig-welding).

## Grinding, storage and handling

CK's **Tungsten Electrodes SDS**, form dated **March 2025**, explicitly includes EWLa-1.5 and EWLa-2 alongside other electrode families. It calls for avoiding dust/fume exposure, adequate local exhaust/general ventilation, hygiene and preventing grinding-residue accumulation. Follow the actual electrode SDS and grinder instructions for dust collection and task-appropriate protection; no universal respirator or ventilation setting follows from the electrode classification. [CK Worldwide, *Tungsten Electrodes Safety Data Sheet*, sections 1, 7 and 8](https://www.ckworldwide.com/asset/67ec30c6b37f7).

The same SDS covers thoriated products and contains thorium-specific provisions. Those provisions must not be attributed to lanthanated rods merely because the document is shared. Conversely, choosing a product without a thorium addition does not remove ordinary dust-control requirements. CK specifies cool, dry, ventilated storage; keep electrode identification and prepared surfaces protected during storage and handling. [CK Worldwide, *Tungsten Electrodes Safety Data Sheet*](https://www.ckworldwide.com/asset/67ec30c6b37f7).