In CWB classifications, which class describes a weld with backing?

In CWB classifications, which class describes a weld with backing?

• A. S class
• B. T class
• C. L class
• D. M class

Answer: (A)

In this classification system, the letters indicate specific welding conditions. The S class is the designation used when a weld is performed with backing material behind the root pass. Backing provides a support surface that helps control the root bead, improve penetration, and influence how the weld is qualified and inspected. That’s why the correct description for a weld with backing is the S class. The other classes represent different conditions and do not describe backing.

In this classification system, the letters indicate specific welding conditions. The S class is the designation used when a weld is performed with backing material behind the root pass. Backing provides a support surface that helps control the root bead, improve penetration, and influence how the weld is qualified and inspected. That’s why the correct description for a weld with backing is the S class. The other classes represent different conditions and do not describe backing.