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                                                                     Exhibit 4.4

                                FOURTH AMENDMENT
                                       TO
                           REVOLVING CREDIT AGREEMENT

     This FOURTH AMENDMENT TO REVOLVING CREDIT AGREEMENT is made and entered
into as of September 26, 2001 (this "Amendment"), among (a) CALIFORNIA STEEL
                                     ---------
INDUSTRIES, INC., a Delaware corporation (the "Borrower"), (b) THE BANKS, (c)
                                               --------
BANK OF AMERICA, N.A., as loan and collateral agent for the Banks (in such
capacity, hereinafter the "Loan and Collateral Agent"), and (d) BANK OF AMERICA,
                           -------------------------
N.A., as documentation and letter of credit agent for the Banks (in such
capacity, hereinafter the "Letter of Credit Agent"). Capitalized terms used but
                           ----------------------
not defined in this Amendment shall have the same meanings to such terms in the
Credit Agreement defined below.

     WHEREAS, the Borrower, the Banks, the Loan and Collateral Agent, the Letter
of Credit Agent and the Arrangers have entered into that certain Revolving
Credit Agreement, dated as of March 10, 1999 (as amended, restated, supplemented
or otherwise modified and in effect from time to time, the "Credit Agreement")
                                                            ----------------
pursuant to which the Banks have extended credit to the Borrower on the terms
set forth therein;

     WHEREAS, the Borrower has requested that the Banks amend the Credit
Agreement upon the terms and subject to the conditions contained herein; and

     WHEREAS, the Banks have agreed to amend the Credit Agreement upon the terms
and subject to the conditions contained herein;

     NOW, THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties agree as follows:

     1.   Amendment to the Credit Agreement. Subject to satisfaction of each of
          ---------------------------------
the conditions set forth in ss.3 below and effective as of the Effective Date,
the Borrower, the Loan and Collateral Agent, the Letter of Credit Agent and the
Banks hereby agree to amend ss.10.5 of the Credit Agreement by deleting the
amount "$34,000,000" contained in clause (c) of such ss.10.5 and substituting in
lieu thereof the amount "$26,000,000".

     2.   Representation and Warranties. The Borrower hereby represents and
          -----------------------------
warrants to each of the Banks, the Loan and Collateral Agent and the Letter of
Credit Agent as follows:

          (a)  Representations and Warranties in Credit Agreement. Each of the
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     representations and warranties of the Borrower contained in the Credit
     Agreement, the other Loan Documents or in any document or instrument
     delivered pursuant to or in connection with the Credit

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                                       -2-

     Agreement (i) were true and correct when made and (ii) after giving effect
     to this Amendment, continue to be true and correct on the date hereof
     (except to the extent of changes resulting from transactions contemplated
     or permitted by the Credit Agreement and the other Loan Documents, as
     amended hereby, and changes occurring in the ordinary course of business
     that singly or in the aggregate are not materially adverse, and to the
     extent that such representations and warranties relate expressly to an
     earlier date).

          (b)  Authority. The execution and delivery by the Borrower of the
               ---------
     Amendment and the performance by the Borrower of its agreements and
     obligations under the Amendment (i) are within its corporate authority (ii)
     have been duly authorized by all necessary proceedings, (iii) do not and
     will not conflict with or result in any breach or contravention or any
     provision of law, statute, rule or regulation to which the Borrower is
     subject or any judgment, order, writ, injunction, license or permit
     applicable to the Borrower so as to materially adversely affect the assets,
     business or any activity of the Borrower, (iv) do not conflict with any
     provision of the corporate charter or bylaws of the Borrower or any
     agreement or other instrument binding upon them, (v) require any waivers,
     consents or approvals by any of its creditors which have not been obtained,
     or (vi) require any approval which has not been obtained.

          (c)  Enforceability of Obligations. The Amendment and the Credit
               -----------------------------
     Agreement, as amended hereby, constitute the legal, valid and binding
     obligations of the Borrower enforceable against the Borrower in accordance
     with their respective terms, except as enforceability is limited by
     bankruptcy, insolvency, reorganization, moratorium or other laws relating
     to or affecting generally the enforcement of creditors' rights and except
     to the extent that availability of the remedy of specific performance or
     injunctive relief is subject to the discretion of the court before which
     any proceeding therefor may be brought.

     3.   Condition to Effectiveness. This Amendment shall become effective as
          --------------------------
of the date hereof subject to satisfaction of each of the following conditions
precedent (the "Effective Date"):
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          (a)  Execution and Delivery of Amendment. This Amendment shall have
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     been executed and delivered to the Loan and Collateral Agent by each of the
     Borrower, the Majority Banks and the Agents.

          (b)  Amendment Fee. The Borrower shall have paid to the Loan and
               -------------
     Collateral Agent a non-refundable amendment fee in an amount equal to
     $40,000 to be distributed equally among the Banks.

     4.   Affirmation and Acknowledgment of the Borrower. The Borrower hereby
          ----------------------------------------------
ratifies and confirms all of its Obligations to the Banks and the

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                                       -3-

Borrower hereby affirms its absolute and unconditional promise to pay to the
Banks the Revolving Credit Loans and all other amounts due under the Credit
Agreement, as amended hereby.

     5.   Miscellaneous Provisions. From and after the date hereof, this
          ------------------------
Amendment shall be deemed a Loan Document for all purposes of the Credit
Agreement and the other Loan Documents and each reference to Loan Documents in
the Credit Agreement and the other Loan Documents shall be deemed to include
this Amendment. Any breach by the Borrower of the covenants and obligations of
the Borrower contained herein shall be an immediate Event of Default. Except as
expressly provided herein, this Amendment shall not, by implication or
otherwise, limit, impair, constitute a waiver of or otherwise affect any rights
or remedies of the Loan and Collateral Agent or the Banks under the Credit
Agreement or the other Loan Documents, nor alter, modify, amend or in any way
affect any of the obligations or covenants contained in the Credit Agreement or
any of the other Loan Documents, all of which are ratified and confirmed in all
respects and shall continue in full force and effect. This Amendment may be
executed in any number of counterparts, but all of such counterparts shall
together constitute but one and the same agreement. Delivery of an executed
counterpart of a signature page by facsimile transmission shall be effective as
delivery of a manually executed counterpart of this Amendment. In making proof
of this Amendment, it shall not be necessary to produce or account for more than
one such counterpart.

     6.   Applicable Law. THIS AMENDMENT IS INTENDED TO TAKE EFFECT AS AN
          --------------
AGREEMENT UNDER SEAL AND SHALL BE CONSTRUED ACCORDING TO AND GOVERNED BY THE
LAWS OF THE STATE OF NEW YORK.

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                                       -4-

     IN WITNESS WHEREOF, the undersigned have duly executed this Amendment as a
sealed instrument as of the date first set forth above.

                                             CALIFORNIA STEEL INDUSTRIES, INC.


                                             By: _______________________________
                                                 Name:  C. Lourenco Goncalves
                                                 Title: President and C.E.O.


                                             BANK OF AMERICA, N.A., as Loan and
                                              Collateral Agent


                                             By: _______________________________
                                                 Name:  Ken Puro
                                                 Title: Vice President

                                             BANK OF AMERICA, N.A., as a Bank
                                              and Letter of Credit Agent


                                             By: _______________________________
                                                 Name:  Jamie Harney
                                                 Title: Vice President

                                             WELLS FARGO BANK, N.A.


                                             By: _______________________________
                                                 Name:  Anthony D. Turner
                                                 Title: Vice President

                                             BANK OF TOKYO-MITSUBISHI, LTD.


                                             By: _______________________________
                                                 Name:  Takeo Sato
                                                 Title: Deputy General Manager

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                                             THE INDUSTRIAL BANK OF JAPAN,
                                              LIMITED


                                             By: _______________________________
                                                 Name:  Yoshiaki Fujikawa
                                                 Title: SVP & Senior Manager