WITNESSETH:

   1

                                                                     EXHIBIT 4.8


                   FIRST AMENDMENT TO TRUST AGREEMENT BETWEEN
                     FIDELITY MANAGEMENT TRUST COMPANY AND
                               QUANEX CORPORATION

         THIS FIRST AMENDMENT, dated as of the first day of November, 1999, by
and between Fidelity Management Trust Company (the "Trustee") and Quanex
Corporation (the "Sponsor").


                                  WITNESSETH:

         WHEREAS, the Trustee and the Sponsor heretofore entered into a Trust
Agreement dated February 1, 1999 with regard to the Quanex Corporation Employee
Savings Plan, the Quanex Corporation Hourly Bargaining Unit Employees Savings
Plan, the Piper Impact 401(k) Plan, the Xxxxxxx-Homeshield 401(k) Savings Plan
and the Xxxxxxx-Homeshield 401(k) Savings Plan for Hourly Xxxxxxxxx Employees
(the "Plan"); and

         WHEREAS, the Trustee and the Sponsor now desire to amend said Trust
Agreement as provided for in Section 14 thereof;

         NOW THEREFORE, in consideration of the above premises, the Trustee and
the Sponsor hereby amend the Trust Agreement by:

         (1)    Amending Schedule "G" by adding the following to the Exchange
                Restrictions for the Quanex Corporation Stock Fund, as follows:

                    Participants who exchange into the Sponsor Stock Fund must
                    wait a minimum of forty-five (45) days prior to exchanging
                    out of the Sponsor Stock Fund.

                    Participants who exchange out of the Sponsor Stock Fund must
                    wait a minimum of forty-five (45) days prior to exchanging
                    back into the Sponsor Stock Fund.

         IN WITNESS WHEREOF, the Trustee and the Sponsor have caused this First
Amendment to be executed by their duly authorized officers effective as of the
day and year first above written.

QUANEX CORPORATION                          FIDELITY MANAGEMENT TRUST COMPANY


By:                                         By:
    --------------------------------            --------------------------------
                             Date               Vice President           Date