Arc Blow is a common, yet easily preventable thing that plagues welding operations. It’s an issue that can cause weld defects, inaccurate welds, and even damaging effects to equipment. But what exactly is it, and how can you prevent it?
Arc Blow is a phenomenon that typically occurs during a magnetic arc welding process when electrical currents interact with a magnetic field and cause an arc deflection. It occurs in a variety of welding applications and can cause weld contamination, decreased productivity, and inaccurate welds.
In some instances, it can even cause tensile and fatigue strength damage, which can lead to severe equipment and infrastructure damage. According to a survey conducted in 2020, more than 45% of welders believe arc blow is one of the most problematic welding issues they experience.
Over half of the welders reported that arc blow had caused significant weld defects, inaccuracy, and equipment damage. As such, the ability to understand and prevent arc blow is critical for any welding operation.
What is Arc Blow in Welding?Arc blow is a welding defect that is caused due to the fluctuation in the arc current during arc welding.
This happens when there is an intense magnetic current flowing between the welding arc, the welding tungsten electrode and the workpiece. The main cause of arc blow is the false magnetic field that is set up around the welding arc, which then causes the welding arc to be drawn away from the welding line in an unexpected pattern, resulting in poor quality welds.
Causes of Arc Blow
- Improper welding technique: Improper technique while welding can cause the arc to be drawn away in an unexpected pattern, resulting in arc blow.
- Improper setup of the welding machine: If the welding machine is not set up properly, it can cause arc blow by creating a false magnetic field and disrupting the welding arc.
- Disturbances in the power supply: A disruption in the power supply can cause the arc to be drawn away from the welding line, resulting in arc blow.
- Use of improper equipment: Using poorly maintained welding equipment that is not up to the standards can cause arc blow as well.
- Welding in a metallic environment: Welding in a metallic environment can cause a false magnetic field to be created, resulting in arc blow.
- Welding incorrect polarity: Incorrect polarity during the welding process can cause arc blow by disrupting the welding arc.
Effects of Arc BlowArc blow can have serious effects on the welding process. It can cause porosity in the welds, making them weak and prone to cracking and failure. Arc blow can also cause undercuts, dents and warping in the welds, resulting in poor quality welds.
Prevention of Arc BlowTo prevent arc blow, the following tips can be followed:
- Maintain correct polarity while welding.
- Use properly set up welding machine.
- Practice proper welding technique.
- Use good quality welding equipment.
- Inspect the workpiece for any other source of magnetic interference.
- Weld in a non-metallic area.
- Use a suitable welding shield to protect against magnetic interference.