As a weld nears the end of the joint a DC arc has a tendency to blow

As a weld nears the end of the joint a DC arc has a tendency to blow

• A. Toward the end of a joint
• B. Toward the beginning of a joint
• C. To the right side of the joint
• D. To the left side of the joint

Answer: (B)

Arc blow in DC welding happens because the welding current creates a magnetic field around the circuit formed by the electrode, workpiece, and return path. As you weld toward the end of a joint, the magnetic loop that returns current to the power source tends to concentrate at the starting end. That concentrated magnetic flux pulls the arc toward that end, so the arc tends to blow toward the beginning of the joint as you near completion. This is why controlling the return path and keeping leads close to the weld can help minimize the effect.

Arc blow in DC welding happens because the welding current creates a magnetic field around the circuit formed by the electrode, workpiece, and return path. As you weld toward the end of a joint, the magnetic loop that returns current to the power source tends to concentrate at the starting end. That concentrated magnetic flux pulls the arc toward that end, so the arc tends to blow toward the beginning of the joint as you near completion. This is why controlling the return path and keeping leads close to the weld can help minimize the effect.