Which assembly technique requires heat and filler metal to join components?

The correct answer is welding, as this assembly technique specifically involves the application of heat to melt the base materials and often a filler metal, which is added to help fuse the components together. During the welding process, when the materials reach the appropriate temperature, they become molten and can combine to form a strong, unified joint as they cool and solidify. This process is critical in various applications where a strong and durable connection is required, especially in metalworking and fabrication.

In contrast, the other methods listed do not involve this combination of heat and filler materials. Screwing uses mechanical fasteners to hold materials together without melting the components. Riveting involves inserting a metal pin and deforming it to create a connection, also without using heat. Adhesive bonding relies on chemical adhesives to join surfaces, rather than melting or fusing the materials. Each of these alternatives has its own applications but does not achieve junctions in the same way that welding does.