Which of the following metals are commonly used for electrodes in resistance spot welding?

In resistance spot welding, electrodes play a crucial role in conducting the electrical current necessary for welding. The correct metals commonly used for electrodes in this process are brass and copper.

Copper is particularly favored due to its excellent electrical conductivity, which is essential for generating the heat required to melt the metal at the welding joint. It also has good thermal conductivity, allowing it to dissipate excess heat quickly, which helps in maintaining the integrity of the electrodes and preventing them from damage during welding.

Brass, an alloy composed mainly of copper along with zinc, is also used for similar reasons. It provides a balance of strength, conductivity, and resistance to wear and oxidation, which is beneficial in the welding environment.

The other materials listed do not typically provide the same levels of conductivity or thermal management required for effective resistance spot welding. This is why brass and copper stand out as optimal choices for electrodes in this application.