What joining process involves heating a metal and introducing a filler rod to form a weld?

The joining process that involves heating a metal and introducing a filler rod to form a weld is welding. In welding, heat is used to melt the base metal along with a filler rod, which is also melted and pools into the joint to create a strong bond when cooled. This process is essential in various engineering applications as it provides a durable and robust connection between metal components.

Welding usually incorporates high temperatures, reaching melting points, and can involve methods such as arc welding, MIG welding, or TIG welding, where the filler material serves to enhance the strength of the joint. The filler material often has similar properties to the base metals being joined, ensuring compatibility and structural integrity.

Other processes like soldering and brazing, while also used for joining materials, typically operate at lower temperatures than welding and involve different materials and methods for joining metals. Soldering primarily uses a filler alloy with a melting point lower than that of the base metals, and brazing involves a filler metal that melts above 450 °C but still below the melting point of the workpieces. Fusing refers to melting the materials together without adding any filler, which is distinct from the process of welding where the filler rod is a critical component.