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Choosing Tungsten Electrodes: What to Look For

Date: 19-01-2023
Welding Consumables Stainless Steel Welding Welding Aluminium

Choosing Tungsten Electrodes - Alphaweld Insights


It’s crucial to use the correct tungsten electrode for the welded material, power source and polarity. You’ll improve your weld quality and save the effort of reworking joints by selecting the proper tungsten. It can be very difficult to TIG weld with the wrong electrode too.

There are many different tungsten electrodes on the market that are colour-graded. In this article we’ll cover which tungsten you need and what kind of work each type is designed for.

Different Tungsten Electrode Types and Classification

Tungsten electrodes can either be pure (green tungsten) or a mixture that includes oxides. Electrodes with oxides like thorium, lanthanum, cerium, zirconium, and others are based on their principal oxide and have an assigned colour according to the AWS A5.12M (ISO 6848) Specification for Tungsten Electrodes for Arc Welding.

Tungsten Electrodes Classification and Current Polarity

Tungsten Electrode

Colour

Classification/ISO 6848

Alloying Oxide

Oxide Mass

Current Polarity

Pure Tungsten

Green

EWP/WP

None

N.A.

Mostly used for AC

Thoriated

Red

EWTh-2/WTh 20

Thorium oxide

1.7–2.2%

DC

Ceriated

Grey

EWCe-2/WCe20

Cerium oxide

1.8-2.2%

AC/DC

Lanthanated

Blue

EWLa-2/WLa 20

Lanthanum oxide

1.8-2.2%

AC/DC

 Zirconiated

White

EWZr-8/WZr 8

Zirconium oxide

0.7-0.9%

AC

Rare Earth Mix

Manufacturer
selects a colour

EWG

Manufacturer identifies alloys

Manufacturer marks the percentages

Depends on manufacturer

Thoriated Tungsten Electrodes (Red)

Red thoriated tungsten electrodes contain 1.7-2.2% thorium oxide (thoria), a radioactive substance, so you must take strong safety precautions when grinding this tungsten electrode. 

Thoriated tungsten is designed for DC TIG welding of all steels, nickel, titanium, and copper alloys. Red tungsten is the most commonly used electrode. It offers excellent arc performance and stability and a low consumption rate. However, if you don’t need to use high amperages and want to avoid radioactivity, the ceriated tungsten below is a suitable alternative.

Ceriated Tungsten Electrodes (Grey)

Grey ceriated tungsten electrodes are alloyed with 1.8-2.2% cerium oxide (ceria). They are not radioactive. You can use ceriated tungsten for both AC and DC TIG welding at lower amperages, however high amps may cause cerium oxide to concentrate at the electrode’s tip. This tendency makes these electrodes best suited for delicate welds and sheet metal work.

These electrodes have good arc start characteristics without spitting and can last a long time. Ceriated tungsten is used for welding steels, aluminium, magnesium, nickel alloys, and titanium.

Lanthanated Tungsten Electrodes (Blue)

Blue lanthanated tungsten electrodes contain 1.8-2.2% lanthanum oxide (lanthana). They are also not radioactive and are an excellent substitute for thoriated tungsten. Blue tungsten works well for DC and AC TIG welding at medium to high amperages, making them a good choice for welding thicker materials.

Many consider lanthanated tungsten to be the best all-purpose electrode. They have good arc stability and a low erosion rate. In addition, you can weld all metals using lanthanated tungsten, from low-alloy steels to titanium, aluminium, magnesium, nickel, and copper alloys. This is an excellent tungsten electrode for stainless steel because it maintains a sharp tip well. As a result, you are less likely to overheat the stainless or contaminate it with tungsten.

Zirconiated Tungsten Electrodes (White)

White zirconiated tungsten electrodes contain 0.7-0.9% zirconium oxide (zirconia). This is the best TIG tungsten for welding aluminium and magnesium alloys. Zirconia tungsten electrodes easily create a ball at the tip and offer better arc stability than pure tungsten (green), making them a better choice for aluminium.

Rare-Earth Tungsten Electrodes (Varying Colours)

Rare-earth tungsten electrodes can have different oxide mixtures as alloying elements. Their composition and use depend on the manufacturer, and they can often have superior performance compared to tungsten with only one oxide.

Purple E3 tungsten electrodes contain a combination of three rare-earth oxides, giving them faster and more reliable arc starts and better tungsten tip stability. They are not radioactive and can be used to weld every metal with AC or DC current. In addition, they remain much cooler than the red thoriated tungsten, prolonging their lifespan and letting you use more amps.

Need Help Choosing Your Tungsten?

Whether you are looking for tungsten electrodes or a high-quality tungsten grinder to shape them, Alphaweld is here for you. To speak with our team, give us a call on (08) 9456 8000 or get in touch and our experts will gladly assist you.