What is fusion welding?

• A. A process in which base metals are melted to form a joint, often with filler material.
• B. A process that joins metals without heating.
• C. A process that uses glue.
• D. A process that only uses mechanical fasteners.

Answer: (A)

Fusion welding joins pieces by melting the base metals to form a molten pool that fuses as it cools, often with filler material added to fill gaps or adjust properties. The key is creating that molten zone at the joint so the metal pieces actually fuse together when it solidifies. This contrasts with methods that join without melting (like mechanical fasteners or some solid-state processes) or use adhesives, where no molten metal pool is formed. Fusion welding is versatile and widely used because it can produce strong, leak-tight joints by relying on the metal’s own bonding as it cools and solidifies.