For a CWB weld that uses backing material, what class is assigned?

For a CWB weld that uses backing material, what class is assigned?

• A. S class
• B. D class
• C. E class
• D. F class

Answer: (A)

The main idea here is that the welding classification system marks whether backing material is used. When a CWB weld incorporates backing material, the condition is captured by assigning the S class. This designation signals that the welding procedure, qualification, and inspection must account for the presence of backing, which affects heat flow, weld geometry, and inspection criteria. Therefore, using backing material properly fits with the S class, making it the correct choice.

The main idea here is that the welding classification system marks whether backing material is used. When a CWB weld incorporates backing material, the condition is captured by assigning the S class. This designation signals that the welding procedure, qualification, and inspection must account for the presence of backing, which affects heat flow, weld geometry, and inspection criteria. Therefore, using backing material properly fits with the S class, making it the correct choice.