What does a welder use high electric current to create for joining metal?

A welder uses a high electric current to create an arc, which is a localized discharge of electricity that generates intense heat. This heat is essential for melting the base metals and filler materials, allowing them to fuse together as they cool. The arc is formed between the welding electrode and the workpiece, establishing a conductive path that delivers the necessary energy for the welding process.

In the context of metal joining, the arc provides precise control over the temperature and allows for the deep penetration needed to create strong welds. The other choices relate to different aspects of welding but do not accurately represent the primary feature utilized in the welding process. Flux, for example, is a material used to clean and protect the molten metal and joint but is not the source of heat in welding. A beam could refer to light or a structural member but is not specific to welding. A joint refers to the connection or interface between two pieces of metal being welded, which is the end goal of the process rather than the technique itself.