Exhibit 5.1

[Letterhead of Barrett & McNagny LLP]



February 27, 2002



Steel Dynamics, Inc.
6714 Pointe Inverness Way, Suite 200
Fort Wayne, Indiana 46804

Re:     Steel Dynamics, Inc.
        Registration Statement on Form S-3

Gentlemen:


We have acted as counsel to Steel Dynamics, Inc., an Indiana corporation (the
"Company"), in connection with the Company's registration of the resale of $22
million of its newly issued shares of common stock, the exact number of shares
to be determined by dividing $7,333,334 by the closing price of the Company's
common stock on the Nasdaq National Market on the second business day prior to
each of three issuance dates-March 1, March 15 and March 29, 2002-as required
under that certain Settlement Agreement dated as of January 28, 2002 (the
"Shares").  This transaction is more fully described in the Company's amended
Registration Statement on Form S-3, filed with the United States Securities and
Exchange Commission, on the date hereof, to which this opinion is attached as
Exhibit 5.1 ("Registration Statement").


This opinion is being furnished in accordance with the requirements of Item
601(b)(5) of Regulation S-K promulgated under the Securities Act of 1933, as
amended.

In rendering the opinion set forth below, we have examined originals or copies,
certified or otherwise identified to our satisfaction, of such documents,
corporate records, certificates of public officials and other instruments as we
have deemed necessary or advisable for the purpose of rendering this opinion.
In our examination, we have assumed the genuineness of all signatures, the
authenticity of all documents submitted to us as originals and the conformity
to the original of all documents submitted to us as copies. As to various
questions of fact material to our opinion, we have relied on the
representations of the Company.

Based on the foregoing, we are of the opinion that the Shares are duly
authorized and, when issued on March 1, March 15 and March 29, 2002, in
accordance with the requirements under the Settlement Agreement, and resold in
accordance with the registration statement, will be legally issued, fully paid
and nonassessable.

Our opinion is limited to the general corporation law of the State of Indiana
and the federal laws of the United States of America. We express no opinions as
to any other laws, statutes, rules or regulations.



We hereby consent to the use of this opinion as Exhibit 5.1 to the Registration
Statement and to the reference to this firm under the caption "Legal Matters."

This opinion is rendered solely to you in connection with the above matter.
This opinion may not be relied upon by you for any other purpose or relied upon
by or furnished to any other person without our prior written consent.

Very truly yours,

/s/ BARRETT & McNAGNY LLP