Welding tungsten electrodes are not resistant to heat, prone to melting, and the tip collapses quickly due to excessive wear. The complete reasons are as follows:
Incorrect polarity connection (the most common fatal cause)
When welding materials such as stainless steel and carbon steel, a direct current positive polarity connection must be used.
Because in this case, the tungsten electrode only needs to withstand 30% of the arc heat, thus the tungsten electrode will have excellent high-temperature resistance and durability.
The wrong approach is to reverse the direct current, in which case 60% of the arc heat will concentrate at the tip of the tungsten electrode, causing it to rapidly melt and collapse within a few seconds due to excessive temperature, significantly shortening its service life.
Please note that only when using pure tungsten electrodes for welding aluminum and magnesium, should the AC mode be used.
Inappropriate current selection, overload
The tungsten electrode diameter is too small, but when the welding current exceeds the safe carrying capacity of this specification.
The heat accumulates continuously, causing the weld tip to rapidly melt and collapse.
For example, if a 1.6-millimeter tungsten electrode is continuously welded with more than 130 amperes, it will definitely wear out quickly. 2.
Frequent spot welding and intermittent high-frequency arc ignition can cause the tungsten electrode to repeatedly endure instantaneous high-temperature impacts, intensifying thermal fatigue and leading to wear.
Poor argon gas protection, accelerated consumption due to high-temperature oxidation
1. The argon gas flow is too small and the pressure is insufficient, unable to remove the heat from the tungsten electrode, lacking gas cooling;
2. There is wind in the site or the workshop has a crosswind that blows away the protective gas, and the air comes into contact with the high-temperature tungsten electrode, causing tungsten to combine with oxygen and nitrogen to form an oxide layer, which has a significantly lower melting point and is prone to melting and consumption;
3. The ceramic nozzle cracks, gets clogged, the nozzle size is too large or too small, the gas layer becomes disordered, and local protection is lost, causing the tungsten electrode to oxidize and be burned away;
4. The argon gas purity is insufficient (with excessive oxygen and water content), which also causes the tungsten electrode to oxidize and become brittle, and is not resistant to heat.
Incorrect tungsten electrode grinding method, concentrated heat at the tip causes it to melt and break
1. The tungsten electrode grinding is too sharp (needle-like style), the cross-sectional area of the tip is too small, and the heat is highly concentrated, making it prone to melting and breaking; for DC welding, the standard grinding angle is 30° to 45°, with a small platform reserved at the top of 0.3 to 0.5mm.
2. The tungsten electrode grinding is eccentric or skewed, the arc shifts and burns the single side of the tungsten electrode, causing local overheating and rapid wear.
3. The tungsten electrode surface retains oil stains, burrs, and debris, and the arc instantaneously causes local high temperature to burn the tungsten electrode.
Incorrect tungsten electrode material grade selection, poor quality
1. Incorrect grade selection: WP pure tungsten is only suitable for AC aluminum welding and has poor heat resistance in DC conditions, being very intolerant to heat; long-term DC welding with pure tungsten will inevitably wear out quickly.
◦ Thorium tungsten WT20 has the strongest high-temperature resistance, but it contains radioactivity and is prohibited in many factories;
◦ The most resistant production automation welding uses WL15/WL20 lanthanum tungsten; ordinary manual use selects WC20 cerium tungsten.
2. Poorly quality non-brand tungsten electrodes have excessive impurities (Fe, Si, Al, oxygen content), reducing the overall melting point, and being prone to softening and melting at high temperatures; regular rare earth tungsten electrodes are doped with lanthanum and cerium oxides, which can enhance the high-temperature creep resistance and are less prone to burning away.
3. The tungsten electrode material has uneven density and is internally loose, and the high-temperature weak position is the first to burn and break.
Environmental factors in the working conditions
1. The enclosed and narrow workstation has poor heat dissipation, causing the welding gun to heat up as a whole, and the tungsten electrode's heat dissipation is blocked;
2. Long-term continuous and uninterrupted welding without intermittent cooling time leads to continuous high-temperature burning and wear.
If you also encounter the issue of welding melting too quickly mentioned above, please feel free to communicate with us. We will discuss and help you resolve this problem together in the future.
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Baoji city, Shaanxi Province ,China
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