Here is a list of the US top 4 steel companies based on revenue and production.
1) Nucor Corp.
2) Freeport-McMoran Inc
3) United States Steel Corp.
4) Alcoa Corp.
5) Steel Dynamics Inc.
Nucor ranked as America's largest steel producer. Nucore posted 20.25B revenue based on 2018 reports. United States Steel Corp. is another notable company posting. $12.24B revenue.
You can research more at https://www.worldsteel.org/