What are arc strikes in the context of welding?

Arc strikes refer to marks or discolored areas that occur outside of the intended weld zone due to stray arcs establishing contact with the base metal during the welding process. They are a result of an electric arc unintentionally striking the surface of the workpiece and can lead to several issues, such as reduced structural integrity in those areas.

When an arc strike occurs, it can create a small localized area of heating, which may alter the properties of the base material, including grain structure and hardness, depending on the extent and temperature of the heat generated. These marks indicate that there was an inappropriate or unintended arc interaction, which is considered a defect in welding practices, as it can compromise the mechanical properties of the metal near the weld zone.

Understanding the nature of arc strikes is crucial for welders, as it emphasizes the importance of proper technique and control in the welding process to avoid affecting the quality of the weld and the underlying material.