The diameter size of tungsten electrodes has a significant impact on their quality and performance, which is mainly reflected in the following aspects:

The diameter size of tungsten electrodes has a significant impact on their quality and performance, which is mainly reflected in the following aspects: 
1. Current-carrying capacity (current-bearing capability) 
    The larger the diameter: the cross-sectional area increases, the conductivity and heat dissipation ability are enhanced, and it can carry higher current without easily overheating. For example, a tungsten electrode with a diameter of 4.0mm is more suitable for high-current welding (such as above 300A) than one with a diameter of 1.6mm. 
    Too small diameter: It is prone to overheating under the same current, leading to accelerated melting and burning of the electrode tip, and even contaminating the weld seam (such as tungsten inclusions). 
2. Arc stability 
    Large diameter electrode: The arc is more concentrated and stable, suitable for deep penetration welding or high-energy beam processes (such as plasma welding). 
    Small diameter electrode: The arc is more flexible, suitable for fine welding (such as thin plate TIG welding), but the arc may drift, requiring higher operational skills. 
3. Service life 
    Insufficient diameter: Using under excessive current will accelerate electrode wear (evaporation or oxidation) and shorten its lifespan. 
    Proper current matching: When the diameter matches the current (such as using a 2.4mm electrode for 150-200A), the electrode wear is minimal and the lifespan is longest. 
4. Machining accuracy and surface quality 
    Diameter tolerance: Precisely machined electrodes (with a tolerance of ±0.01mm, for example) can ensure arc consistency, while dimensional fluctuations in inferior electrodes may lead to process instability. 
    End grinding: The smaller the diameter, the more difficult it is to grind the tip (e.g., a 0.5mm electrode requires specialized grinding equipment). 
5. Applicable processes and materials 
    High-frequency/pulse welding: Small-diameter electrodes (such as 1.0mm) exhibit faster response and are suitable for precise control. 
    Special alloy electrodes: The diameter selection of doped materials such as thorium tungsten and cerium tungsten needs to consider both current carrying capacity and radioactive/environmental protection requirements. 
Selection suggestions 
    Reference current range: 
    Diameter (mm) DC welding current (A) AC welding current (A) 
    1.0 10-60 10-40 
    1.6 50-100 40-80 
    2.4 100-200 80-160 
    3.2 200-300 160-250 
    4.0+ above 300 above 250 
    Application Scenario: 
        Sheet welding: Prefer small diameter (1.0-2.4mm). 
        Heavy industrial thick plates: Requires large diameter (above 3.2mm) in conjunction with high current. 
Key points related to quality 
    Risk of inferior electrodes: Uneven diameter and high impurity content can lead to arc deviation and shortened lifespan. 
    Standard certification: Electrodes that comply with standards such as AWS/ISO (e.g., EWCe-2) ensure consistency in size and performance. 
To optimize welding quality and efficiency, the reasonable selection of diameter requires a comprehensive consideration of current, process, and electrode material, while ensuring machining accuracy.