Which weld is made by melting the edges of two pieces of metal together?

• A. Fillet weld
• B. Fusion weld
• C. Plug weld
• D. Spot weld

Answer: (B)

The correct answer is fusion weld, as it refers to the process of joining two pieces of metal by melting their edges together. In a fusion weld, the high temperatures generated by the welding process cause the base metals to melt and fuse without the need for additional filler material. This method creates a strong bond by allowing the molten edges to combine as they cool and solidify.

In contrast, options like fillet weld, plug weld, and spot weld involve different techniques. A fillet weld typically connects two surfaces at a perpendicular angle and often uses filler material to bridge the joint. A plug weld is created by drilling a hole in one piece of metal, then welding the other piece to it, which differs from the direct melting of edges. Similarly, a spot weld involves the application of heat to specific points to create welds, usually used to join overlapping sheets, rather than melting the edges of both pieces entirely. Thus, the methodology and the results differ significantly among these types of welds, making fusion weld the most accurate choice for the definition provided.