Certified Welding Inspector Practice Exam

What is the function of accelerating potential in electron beam welding?

1. To stabilize the welding arc

2. To increase the temperature of the base metal

3. To impart velocity to the electrons

4. To control the depth of penetration in welding

The correct answer is: To impart velocity to the electrons

The function of accelerating potential in electron beam welding is to impart velocity to the electrons. In this process, a high-voltage electric field is used to accelerate the electrons emitted from the cathode. This acceleration increases the kinetic energy of the electrons, allowing them to travel at high speeds toward the workpiece. When these high-velocity electrons hit the material being welded, they transfer their energy in the form of heat, melting the base metal and creating a weld pool. The higher the accelerating potential, the greater the velocity of the electrons and, consequently, the more energy available for the welding process. This increased energy focuses on a small area, making electron beam welding capable of achieving deep penetration and a narrow heat-affected zone, which is particularly valuable in various applications, including thin-walled assemblies and when welding difficult-to-join materials. This function is crucial for ensuring effective melting and bonding of materials in the welding process.