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Contraindications of TIG Welding ProcessⅠ

China tig welding guns suppliers share with you.
1. Avoid using DC reverse welding in general welding:
In DC Tungsten Arc Welding, the anode generates much more heat than the cathode. Therefore, when welding with DC positive connection (workpieces are connected), the tungsten electrode is not easy to overheat because of the small amount of heat. Tungsten electrodes of the same diameter can use larger current. At this time, the workpiece has a large amount of heat, a large penetration depth, and high productivity. The tungsten hot electron emission ability is stronger than the workpiece, which makes the arc stable and concentrated. Therefore, most metals (except aluminum, magnesium and their alloys) should be DC forward welding.
The situation is the opposite to that of DC reverse welding, which is generally not recommended.
2. The rectangular half-wave argon arc welding negative half-wave energization time proportion should not be too large:
Rectangular wave AC tungsten arc welding can change the proportion of positive and negative half-wave energization time to match the DC component and adjust the strength of the cathode cleaning. However, the appropriate minimum ratio should be selected according to the welding conditions so that it can meet the cleaning requirements. The need for an oxide film can also achieve the maximum penetration and the smallest tungsten electrode loss. If the ratio is too large, a lighter cathode cleaning effect can be obtained, but the tungsten electrode will be severely burned, and the molten pool will become shallow and wide, which is not good for welding.

3. When the welding current is too large, don't use the tip cone tungsten electrode:
When the welding current is large, the use of a narrow-diameter tapered tungsten electrode will cause the current density to be too large, causing the end of the tungsten electrode to overheat and melt and increase burnout. At the same time, the arc half point will also extend to the conical surface of the tungsten electrode end, which will cause the arc post to expand significantly and fluctuate instably, which will affect the weld formation. Therefore, a tungsten electrode with a relatively large diameter should be used when welding at high currents, and its end should be ground to a blunt cone angle or a flat top to be used.
4. The gas flow and nozzle diameter should not exceed the expected range:
Under certain conditions, there is an optimal range for gas flow and nozzle diameter. For manual argon arc welding, when the flow rate is 5-25L / min, the corresponding nozzle diameter is 5-20mm. Within this range, the airflow is too small or the nozzle diameter is too large, which will make the airflow stiffness poor, the ability to exclude the surrounding air is weak, and the protection effect is not good; if the airflow is too large or the nozzle diameter is too small, it will cause The formation of turbulence not only reduces the scope of protection, but also entrains air and reduces the protection effect.
5. Gas shielded welding avoids excessive welding speed:
The welding speed is mainly determined by the thickness of the workpiece, and cooperates with the welding current and preheating temperature to ensure that the required penetration and width are obtained. However, in high-speed automatic welding, the influence of welding speed on the gas protection effect must also be considered, and excessive welding speed should not be used. Because the welding speed is too high and the protective airflow is severely biased, it may be that the tungsten extreme part, the arc column and the molten pool are exposed to the air, which affects the protection effect.
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