EXHIBIT 23.1 INDEPENDENT AUDITORS' CONSENT We consent to the incorporation by reference in the Registration Statements of Steel Dynamics, Inc. (Forms S-8 Nos. 333-19541, 333-27549 and 333-55888; and Form S-3 No. 333-82210 and Form S-3 No. 333-103672) of our report dated January 24, 2003, except for Note 14, as to which the date is March 14, 2003, with respect to the consolidated financial statements of Steel Dynamics, Inc. included in the Annual Report (Form 10-K) for the year ended December 31, 2002. /s/ Ernst & Young LLP Fort Wayne, Indiana March 27, 2003