What is arc-extinguishing current?

Arc-ending current is a key parameter used in the final stage of welding to smoothly extinguish the arc, fill the crater, and reduce welding defects by reducing the current. It is commonly used in processes such as TIG welding and CO₂ welding.

📌 Definition and Function: Arc-ending current refers to the low current state that the welding machine automatically switches to after releasing the welding torch switch or pressing the stop button during the welding process. It is used to control the arc behavior during the final stage of the weld. Its core functions include:

Cavity filling: Preventing dents or cracks from forming at the weld pool tail due to rapid cooling;
Reducing the molten ball size: In CO₂ welding, reducing the extinguishing current can decrease the diameter of the molten ball at the wire end, improving re-ignition performance;
Smooth transition: Preventing spatter or porosity caused by sudden current drops.

Practical applications and precautions:
Thin plate welding: The extinguishing current needs to be lower (e.g., the starting current in TIG welding is less than the welding current) to avoid burn-through;
Parameter matching: The extinguishing current needs to be adjusted in conjunction with the extinguishing voltage. For example, in CO₂ welding, a voltage of 18V matched with a current of 160A can optimize the molten ball size;
Operating techniques: Using the circular finishing method or back-welding method can further improve the crater filling effect.