Question

Which of the following statements is/are CORRECT with respect to fusion welding and solid-state welding of metals and alloys?

• A. Thermomechanically affected zone is found in the fusion welding of pure metals.
• B. Partially melted zone is NOT found in the fusion welding of pure metal.
• C. Diffusion bonding is one type of solid-state welding process.
• D. Partially melted zone is found in the fusion welding of alloys with a large freezing range.

Hint:

In fusion welding of alloys with a large freezing range, a partially melted zone can exist. For solid-state processes like diffusion bonding, the material is not melted but instead joined by atomic diffusion.

Answer 1

The Correct Option is B, C, D

Let's evaluate each statement:

- (A) Thermomechanically affected zone is found in the fusion welding of pure metals:
- Incorrect: In fusion welding, the thermomechanically affected zone (TMAZ) is typically not defined in the same way as in other welding processes, especially for pure metals. TMAZ is more common in processes like friction stir welding.

- (B) Partially melted zone is NOT found in the fusion welding of pure metal:
- Correct: For pure metals, fusion welding typically involves melting the material completely, and no partially melted zone is typically observed, as the material is either fully molten or solidified.

- (C) Diffusion bonding is one type of solid-state welding process:
- Correct: Diffusion bonding is indeed a type of solid-state welding, where the materials are joined at elevated temperatures without melting, relying on diffusion to form a bond.

- (D) Partially melted zone is found in the fusion welding of alloys with a large freezing range:
- Correct: In alloys with a large freezing range, a partially melted zone can form during fusion welding. This zone exists between the fully molten pool and the solidified base material, as the alloy freezes unevenly.

Thus, the correct answers are Option B, C, and D.

Step 1: Analyzing each option
- Option (A): Thermomechanically affected zone is found in the fusion welding of pure metals.
- Incorrect: As explained, this is not typically observed in fusion welding of pure metals.

- Option (B): Partially melted zone is NOT found in the fusion welding of pure metal.
- Correct: This is true for pure metals in fusion welding.

- Option (C): Diffusion bonding is one type of solid-state welding process.
- Correct: Diffusion bonding is indeed a solid-state welding process.

- Option (D): Partially melted zone is found in the fusion welding of alloys with a large freezing range.
- Correct: This is true for alloys with a large freezing range, such as steel.

Step 2: Conclusion
The correct answers are Option B, C, and D.