Primary Metal Manufacturing

Primary metal manufacturing (NAICS 331) covers the smelting, refining, rolling, drawing, and casting of ferrous and nonferrous metals from ore and scrap. Steel production dominates the subsector, with the US operating roughly 100 steel mills producing approximately 80 million short tons annually. Nucor Corporation and Steel Dynamics (SDI) lead the domestic industry as electric arc furnace (EAF) operators, while US Steel and Cleveland-Cliffs anchor the remaining integrated blast furnace capacity.

The structural shift from blast furnace to EAF production defines the modern US steel industry. EAF mills now produce over 70% of domestic steel output, using scrap metal and direct-reduced iron (DRI) as feedstock rather than iron ore and coke. Nucor's DRI facility in Trinidad and Cleveland-Cliffs' HBI plant in Toledo, Ohio illustrate the industry's investment in securing metallic feedstock for EAF operations. This transition carries significant implications for energy consumption, carbon emissions, and geographic distribution, as EAF mini-mills operate profitably at smaller scale and locate near scrap supply and end markets.

Aluminum smelting has largely exited the US due to electricity cost disadvantages, with only a handful of operational smelters remaining, including Century Aluminum's facilities in Kentucky and South Carolina. The US instead imports primary aluminum and focuses domestic capacity on rolling, extruding, and recycling. Section 232 tariffs imposed in 2018 on imported steel and aluminum continue to shape trade flows and domestic pricing, maintaining a price premium for US-produced metal that supports domestic mill investment.