The blowing-arc-effect during welding
In arc welding, there is a subtle force that is often overlooked but has a significant impact on the quality of the weld: the blowing-arc-effect. This phenomenon can be both a challenge and a tool for welders, depending on how it is utilized.
The phenomenon of the blowing-arc-effect
Turbulence can occur at the tip of the electrode or stud, which can introduce unwanted gases into the weld pool. The consequences can be manifold, from oxidation and burns to pores in the weld seam. The blowing-arc-effect only occurs when welding with an arc.
Causes and effects
The blowing-arc-effect is caused by the electromagnetic fields that inevitably form around current-carrying conductors. These magnetic fields interact with each other and create turbulence, which can "flush" air and welding gas into the weld pool and thus impair the welding quality. An experienced welder can often recognize the blowing-arc-effect by the fact that the stud is welded more strongly on one side than on the opposite side, accompanied by an uneven flow and heavy spattering during the welding process.
Illustration of the blowing-arc-effect
Using the blowing-arc-effect to your advantage
Despite its potentially negative effects, the blowing-arc-effect can also be used to advantage, particularly in certain welding applications such as drawn arc stud welding in the PC position, i.e. horizontal welding. In such cases, gravity can cause the molten material to flow downwards. If the arc is deflected slightly upwards, a uniform weld with a closed bead and no undercut can be created.
Welders can take specific measures to utilise the blowing-arc-effect for a uniform weld seam without undercutting. By attaching earth clamps below the weld and aligning the stud welding gun in a position in which the cable bend is also below the weld, the arc can be deflected slightly upwards. At the same time, the welding current can be increased slightly and the welding time minimised slightly to achieve optimum results.
Conclusion
The blowing-arc-effect may seem like an undesirable phenomenon at first glance, but with the right understanding and application, it can become a valuable tool for welders. By specifically controlling and utilising the blowing-arc-effect, welders can improve the quality of their welds and achieve good welding results.
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