On March 15, 2018, the full text of the presidential proclamations for the steel and aluminum tariffs was published in the Federal Register. The proclamations include the annexes, which modifies chapter 99 of the Harmonized Tariff Schedule.
Heading 9903.80.01 (Iron and steel products) and heading 9903.85.01 (Aluminum products) set forth additional customs duty rates from all countries, except for Canada and Mexico. The Secretary of Commerce may provide other exclusions from the 9903.80.01 and 9903.85.01 headings.
The Federal Register notices may be found here:
And here:
https://www.federalregister.gov/documents/2018/03/15/2018-05477/adjusting-imports-of-aluminum-into-the-united-states