EXHIBIT 3.7

CERTIFICATE OF INCORPORATION

MS (TENNESSEE), INC.

(Now known as Marshall Steel, Inc.)(1)

FIRST: The name of the corporation is

MS (TENNESSEE), INC.

SECOND: The registered office of the corporation is to be located at 32 Loockerman Square, Suite L-100, in the City of Dover, County of Kent, State of Delaware. The name of its registered agent at that address is The Prentice-Hall Corporation System, Inc.

THIRD: The purpose of the corporation is to engage in any lawful act or activity for which corporations may be organized under the General Corporation Law of Delaware.

FOURTH: The corporation shall have the authority to issue 1,000 shares of common stock, which shall each be for $0.01 par value.

FIFTH: The name and mailing address of the incorporator are as follows:

Amy Y. Kim

Proskauer Rose Goetz & Mendelsohn

1585 Broadway

New York, NY 10028

SIXTH: Whenever a compromise or arrangement is proposed between this corporation and its creditors or any class of them and/or between this corporation and its stockholders or any class of them, any court of equitable jurisdiction within the State of Delaware may, on the application in a summary way of this corporation or of any creditor or stockholder thereof or on the application of any receiver or receivers appointed for this corporation under the provisions of Section 291 of Title 8 of the Delaware Code or on the application of trustees in dissolution or of any receiver or receivers appointed for this corporation under the provisions of Section 279 of Title 8 of the Delaware Code order a meeting of the creditors or class of creditors, and/or of the stockholders or class of stockholders of this corporation, as the case may be, to be summoned in such manner as the said court directs. If a majority in number representing three fourths in value of the creditors or class of creditors, and/or of the stockholders or class of stockholders of this corporation, as the case may be, agree to any compromise or arrangement and to any reorganization of this corporation as a consequence of such compromise or arrangement, the said compromise or arrangement and the said reorganization shall, if sanctioned by the court to which the said application has been made, be binding on all the creditors or class of creditors, and/or on all the stockholders or class of stockholders, of this corporation, as the case may be, and also on this corporation.

SEVENTH: To the fullest extent that elimination or limitation of the liability of directors is permitted by law, as the same is now or may hereafter be in effect, no director of the corporation shall be liable to the corporation or its stockholders for monetary damages for breach of his or her fiduciary duty as a director.

EIGHTH: The corporation shall, to the fullest extent permitted by law, as the same is now or may hereafter be in effect, indemnify each person (including the heirs, executors, administrators and other personal representatives of such person) against expenses including attorneys’ fees, judgments, fines and amounts paid in settlement, actually and reasonably incurred by such person in connection with any threatened, pending or completed suit, action or proceeding (whether civil, criminal, administrative or investigative in nature or otherwise) in which such person may

(1)  * The name of the corporation was changed to Marshall Steel, Inc. pursuant to a Certificate of Amendment filed April 8, 1993.

be involved by reason of the fact that he or she is or was a director or officer of the corporation or is or was serving any other incorporated or unincorporated enterprise in such capacity at the request of the corporation.

NINTH: Unless, and except to the extent that, the by-laws of the corporation shall so require, the election of directors of the corporation need not be by written ballot.

TENTH:  The corporation hereby confers the power to adopt, amend or repeal bylaws of the corporation upon the directors.