Integrated Mills and Mini Mills

U. S. Steel uses two different processes for making steel: integrated and mini mill. The integrated process relies on blast furnaces and basic oxygen furnaces while the mini mill process uses electric arc furnaces (EAFs). Each process uses different materials and energy sources, generating varying levels of GHG emissions.

U. S. Steel works hard to minimize the impacts of our steelmaking processes. Our company is developing capabilities to produce steel with lower GHG emissions that meets all the performance standards of our existing steel grades. Read more about our sustainable steels in our Inspiring Innovation section.

Click here to see how how we make steel. 

How We Make Steel Image

How We Make Steel



At U. S. Steel, our mission of delivering profitable steel solutions for people and planet underlies everything we do. In 2023, supported by our Board of Directors (Board), we continued our work to fulfill this mission by executing our strategy to deliver the BEST for all our stakeholders.
Our culture is based on our S.T.E.E.L. Principles: Safety First; Trust and Respect; Environmental Stewardship; Excellence and Accountability; and Lawful and Ethical Conduct. We expect our employees and members of our Board to take personal responsibility to “do what’s right,” and our Code of Ethical Business Conduct serves as the foundation for the actions of our employees and directors. To further ensure that employees understand the Company’s expectations and all applicable rules, we provide annual ethics and compliance training to our employees and share communications about key compliance topics, including senior management messages underscoring the importance of doing business with integrity. In addition, through our annual policy certification process, employees of U. S. Steel Košice (USSK) in Košice, Slovakia, non-represented employees in the United States, and members of our Board certify their ongoing compliance with our Code of Ethical Business Conduct.