In 2004, Mordashov started investing in US steel companies, purchasing companies in Dearborn, MI and Columbus, MS. The acquisition included the Rouge Plant in Dearborn. He received a loan from the United States Department of Energy to renovate and refurbish the manufacturing plants in Dearborn. The value of the loan, over $370 million, was revoked in 2012, after growing political tensions between the US and Russia.
Between 2004 and 2014, Mordashov and Severstal invested up to $3 billion in both the Dearborn and Columbus plants. In 2011 he sold a number of US assets in Ohio, Maryland and West Virginia to the Renco Group, owned by industrialist Ira Rennert. By 2014 all of Severstal's US investments had been sold for a total of $2.3 billion.