What is a Tungsten Electrode?

I. Basic Characteristics of Tungsten Electrodes

Tungsten electrodes produced by Zhuzhou HAO CARBIDE have a melting point of 3410–3422°C, allowing them to maintain structural stability without melting or deforming in high-temperature arc environments. Their low coefficient of thermal expansion, high thermal conductivity, and excellent electrical conductivity ensure dimensional stability and arc maintenance. Furthermore, their moderate resistivity, high Young's modulus, and exceptional high-temperature creep resistance allow the electrodes to maintain rigidity and shape stability under long-term high temperatures and large currents. A low arc erosion rate and high tensile strength improve the wear resistance of the tip and extend its service life.

Basic Characteristics of Tungsten Electrodes

Property Category	Parameters	Description
Purity	≥99.95%≥99.95%	Affects electrical conductivity and arc stability.
Melting Point	Approx. 3410–3422∘C3410–3422∘C	High-temperature stability; resists melting and deformation.
Thermal Expansion Coeff.	Approx. 4.5×10−6/∘C4.5×10−6/∘C	Good dimensional stability; low thermal deformation.
Thermal Conductivity	Approx. 168–173 W/(m⋅K)168–173 W/(m⋅K)	Favors heat dissipation; reduces localized overheating.
Resistivity	Approx. 5.4–5.5×10−8 Ω⋅m5.4–5.5×10−8 Ω⋅m	Ensures stable conductivity and arc maintenance.
Young's Modulus	Approx. 410–411 GPa410–411 GPa	High rigidity; strong resistance to deformation.
Work Function	Approx. 4.55–4.6 eV4.55–4.6 eV	Affects arc starting and arc stability performance.
Current Capacity	Diameter dependent (e.g., Φ2.4mm≈150–250 ADCΦ2.4mm≈150–250 ADC )	Affects allowable welding current range and lifespan.
Vapor Pressure	Low	Low material loss at high temperatures.
Chemical Stability	Stable in inert gases	Unstable in oxidizing environments.
Arc Erosion Rate	Relatively Low	Affects consumption speed and service life.
High-Temp Creep	Strong	Resists deformation under long-term high temperatures.
Cathode Emission	Improved after doping	Enhances low-current arc starting performance.

II. Main Types of Tungsten Electrodes

Based on material composition, Zhuzhou HAO CARBIDE offers various types of tungsten electrodes, including:

1. Pure Tungsten Electrodes: Suitable for AC aluminum welding and applications with lower requirements; they form a stable balled end in AC arcs.

2. Ceriated Tungsten (WC): Commonly used for DC welding of stainless steel and carbon steel thin sheets; they offer easy arc starting and high stability in low-current environments.

3. Lanthanated Tungsten (WL): Ideal for alternating DC and AC welding of stainless steel and aluminum alloys, providing excellent comprehensive performance.

4. Thoriated Tungsten (WT): Suitable for high-load DC welding of carbon steel, stainless steel, nickel alloys, and titanium alloys.

5. Zirconiated Tungsten (WZ): Maintains a spherical tip easily during high-quality AC welding of aluminum and magnesium alloys, reducing metal contamination.

6. Yttriated Tungsten (WY): Applied in the aerospace industry, precision equipment, and specialized high-requirement welding scenarios.

Main Types of Tungsten Electrodes

Type	Color Code	Composition	Features
Pure Tungsten	Green	W≥99.95%W≥99.95%	Low cost; average electron emission capability.
Ceriated Tungsten	Grey	∼2% CeO2∼2% CeO2	Non-radioactive; excellent low-current arc starting.
Lanthanated Tungsten	Blue / Gold	1.5%–2% La2O31.5%–2% La2O3	Low burn-off rate; suitable for both AC and DC.
Thoriated Tungsten	Red	∼1.5%–2% ThO2∼1.5%–2% ThO2	High current capacity; stable arc; superior emission.
Zirconiated Tungsten	Brown	0.8% ZrO20.8% ZrO2	Excellent stability for AC welding.
Yttriated Tungsten	Blue	Proper amount of Y2O3Y2O3	High compressive strength; long/thin arc; deep penetration.

III. Common Specifications and Parameters

The diameter of Zhuzhou HAO CARBIDE tungsten electrodes typically ranges from 0.25mm to 6.4mm. The most common industrial sizes are 1.0mm, 1.6mm, 2.4mm, and 3.2mm. These, combined with specific polarity, tip geometry, and current parameters, allow for precise control of arc shape and heat input.
Standard lengths range from 75mm to 600mm, with the 150mm specification being the most widely used in TIG welding due to its portability and ease of storage. Regarding tip geometry, a pointed tip is preferred for DC welding, while a balled or flat end is designed for AC welding to adapt to different arc conditions.

Common Specifications and Parameters

Specification Category	Parameters / Description
Diameter	0.25mm–6.4mm0.25mm–6.4mm
Length	75mm–600mm75mm–600mm
Tip Geometry	DC Welding: Ground to a sharp point. <br> AC Welding: Balled or flat end.

IV. Manufacturing Process

The primary production method for Zhuzhou HAO CARBIDE tungsten electrodes is powder metallurgy:

1. Mixing: High-purity tungsten powder is mixed uniformly with a proportional amount of rare earth oxide powder.

2. Compacting: The mixed powder is pressed into a dense green compact using isostatic or cold pressing.

3. Sintering: The compact is sintered at temperatures above 2000°C in a vacuum or hydrogen-protected environment to increase density and uniformity.

4. Processing: The sintered billet undergoes pressure processing such as forging and drawing to form rods.

5. Finishing: Finally, the rods undergo grinding, polishing, and final tip shaping to meet precision specification requirements.

V. Applications of Tungsten Electrodes

l TIG Welding (Argon Arc Welding): This is the primary application. As a non-consumable electrode, it generates a stable arc while remaining un-melted. It is widely used for precision welding of stainless steel, aluminum alloys, and titanium alloys in aerospace, pressure vessels, and precision manufacturing.

l Plasma Processing: Used as a cathode discharge source in plasma arc welding and cutting equipment. The high-temperature arc ionizes gas to form a plasma jet, enabling high-energy-density processing of medium-to-thick metal materials with high speed and a small heat-affected zone.

l Vacuum Electronic Devices: Used as electron emitters in gas discharge tubes, vacuum coating equipment, and various electron emission devices. They rely on high-temperature stability and strong electron emission capabilities to maintain stable discharge in high-temp or low-pressure environments.

VI. Precautions for Use

When using Zhuzhou HAO CARBIDE tungsten electrodes in GTAW (TIG) or plasma processing, users should pay close attention to:

l Polarity Selection: Ensuring the correct current type (DCEN, DCEP, or AC) for the material.

l Size Matching: Choosing the correct diameter for the intended current load.

l Tip Geometry: Proper grinding and shaping of the tip to control the arc.

l Environmental Factors: Ensuring proper shielding gas flow.

l Storage and Maintenance: Keeping electrodes dry and free from contamination.

l Environmental Requirements: Proper handling and disposal (especially for thoriated types) to meet safety standards.

Usage Precautions for Tungsten Electrodes

Usage Precaution	Description
Current & Polarity	DC: Prefer Ceriated, Thoriated, or Lanthanated. <br> AC: Prefer Zirconiated or Lanthanated.
Thickness & Diameter	Thin plate ( <3mm<3mm ): Use Φ1.0–1.6mmΦ1.0–1.6mm . <br> Thick plate ( >6mm>6mm ): Use Φ2.4–3.2mmΦ2.4–3.2mm .
Tip Adaptation	DC: Grind to a sharp point. <br> AC: Use a balled or flat end.
Storage & Environment	Store in a dry, clean, non-corrosive gas environment; prevent impact or squeezing.
Wear & Replacement	Regularly inspect tip morphology; replace worn or burnt electrodes promptly.
Eco & Protection	Prioritize non-radioactive alternatives (Ceriated/Lanthanated) over thoriated types.

Carbide Rods Products

Hardness HRA 94 unground solid tungsten carbide rods

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HAO Carbide Co., LTD.

Catherine Tang
Tel: +86-731-22199705
Fax: +86-731-28260602
Mob: +86-13975383023
Email: Catherine@haocarbide.com
Web: www.hao-carbide.com

Address: Building 3, Power Valley Industrial Park, Zhuzhou City, Hunan Province, China