Question

Which of the following statements is or 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:

For welding questions, remember: Pure metals do not show a partially melted zone, alloys with wide freezing range do. Diffusion bonding is always a solid-state welding method.

Answer 1

The Correct Option is B, C, D

Step 1: Recall definitions of zones in welding.
- In fusion welding, three zones can form: the weld metal zone, the heat affected zone, and in the case of alloys, a partially melted zone.
- Pure metals do not exhibit a partially melted zone because they have a sharp melting point.
- The thermomechanically affected zone is significant in solid-state processes like friction stir welding, not in fusion welding of pure metals. Step 2: Evaluate each statement.
- Statement (A): Thermomechanically affected zone is not found in fusion welding of pure metals. Therefore, this statement is incorrect.
- Statement (B): Since pure metals melt sharply, no partially melted zone is formed in their fusion welding. This statement is correct.
- Statement (C): Diffusion bonding is indeed classified as a solid-state welding process. This statement is correct.
- Statement (D): In alloys with a wide freezing range, there exists a region that is partially solid and partially liquid during welding. Hence a partially melted zone is present. This statement is correct. Step 3: Final conclusion.
The correct statements are (B), (C), and (D). \[ \boxed{\text{Correct Answer = (B), (C), and (D)}} \]