Sean Gallup/Getty President Donald Trump recently rolled out hefty tariffs on aluminum and steel. Aluminum and steel are metals are needed to build infrastructure and to ensure national security. Countries in North America have been cooperating for many decades to guarantee supply chains for both aluminum and steel. As the global rhetoric around trade heats up, aluminum and steel are two metals that have been unexpectedly thrust into the international spotlight. Both metals are getting considerable attention as journalists and pundits analyze how tariffs may impact international markets and trade relations.