EXHIBIT 4.1








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                             ALLEGHENY LUDLUM CORPORATION

                                         And

                           ALLEGHENY TELEDYNE INCORPORATED

                                          To

                              THE CHASE MANHATTAN BANK,
                                      as Trustee

                                   ---------------


                                      INDENTURE

                            Dated as of December 15, 1995

                                   ---------------


                             FIRST SUPPLEMENTAL INDENTURE

                             Dated as of August 15, 1996

                                   ---------------


                     Guarantee by Allegheny Teledyne Incorporated



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                    FIRST SUPPLEMENTAL INDENTURE ("First Supplemental
          Indenture"), dated as of August 15, 1996, by and among ALLEGHENY
          LUDLUM CORPORATION, a corporation duly organized and existing
          under the laws of the Commonwealth of Pennsylvania (herein called
          the "Company"), having its principal executive offices at 1000
          Six PPG Place, Pittsburgh, Pennsylvania 15222, ALLEGHENY TELEDYNE
          INCORPORATED, a corporation duly organized and existing under the
          laws of the State of Delaware (herein called the "Guarantor"),
          having its principal executive offices at 1000 Six PPG Place,
          Pittsburgh, Pennsylvania 15222, and THE CHASE MANHATTAN BANK,
          successor by merger to The Chase Manhattan Bank (National
          Association), a New York State Banking Corporation, as Trustee
          (herein called the "Trustee").

                               RECITALS OF THE COMPANY

                    The Company and the Trustee entered into an Indenture,
          dated as of December 15, 1995 (herein called the "Indenture"),
          pursuant to which the Company's 6.95% Debentures Due December 15,
          2025 (herein called the "Securities") have been issued.

                    On the date of this First Supplemental Indenture, a
          wholly-owned subsidiary of the Guarantor has merged with and into
          the Company with the Company being the surviving corporation (the
          "Merger"), whereupon the Company has become a wholly-owned
          subsidiary of the Guarantor.

                    The Company desires to obtain an exemption from the
          requirements of filing with the Securities and Exchange
          Commission an annual report and such periodic information,
          documents and other reports as are required by Sections 13 and
          15(d) of the Securities Exchange Act of 1934 with respect to the
          Company during and for its current fiscal year and thereafter,
          and for that purpose the Company and the Guarantor are willing to
          supplement the provisions of the Indenture by adding thereto the
          Guarantee set forth in this First Supplemental Indenture pursuant
          to Article Nine of the Indenture.  Such Guarantee is for the
          benefit, and will not adversely affect the interests, of the
          Holders of Outstanding Securities.

                    The Company has delivered to the Trustee an Officers'
          Certificate and an Opinion of Counsel, each stating that the
          Merger complies with Article Eight of the Indenture and that all
          conditions precedent therein provided for relating to the Merger
          have been complied with, and that the execution of this First
          Supplemental Indenture is permitted by the Indenture.

                    NOW, THEREFORE, THIS FIRST SUPPLEMENTAL INDENTURE
          WITNESSETH:

                    For and in consideration of the premises and the
          covenants contained herein and intending to be legally bound
          hereby, it is mutually agreed for the equal and proportionate
          benefit of all Holders of the Securities, as follows: 


                                     ARTICLE I-1

                                      Guarantee


                    SECTION I-101.  Obligation of Guarantor.  The Guarantor
          hereby irrevocably guarantees to the Holders of the Securities
          and to the Trustee on behalf of such Holders the due and punctual
          payment of the principal of and premium, if any, and interest on
          the Securities, when and as the same shall become due and
          payable, whether upon acceleration, redemption or stated
          maturity, in accordance with the terms of the Securities and the
          Indenture (herein called the "Guarantee"), and in case of the
          failure of the Company punctually to make any such payment of
          principal, premium, if any, or interest, the Guarantor hereby
          agrees to make any such payment, or cause any such payment to be
          made, punctually when and as the same shall be due and payable in
          accordance with the terms of the Securities and the Indenture,
          and as if such payment were made by the Company.  The Guarantor
          does not hereby guarantee the performance by the Company of any
          other of the Company's covenants, agreements or obligations under
          the Securities or the Indenture.  The Guarantee shall be deemed
          to be a third-party beneficiary agreement for the benefit of the
          Holders of the Securities from time to time.

                    Upon any failure by the Guarantor to make due and
          punctual payment of the principal, premium, if any, and/or
          interest with respect to which a failure by the Company to make
          due and punctual payment in accordance with the terms of the
          Securities and the Indenture shall have occurred, the Trustee and
          the Holders of the Securities shall have the same rights, powers
          and duties, exercisable in accordance with the same terms and
          conditions and subject to the same limitations, as apply under
          the Indenture with respect to such failure by the Company.

                    SECTION I-102.  Reports, Etc. by Guarantor.  The
          Guarantor shall file with the Trustee and the Commission, and
          transmit to Holders, such information, documents and other
          reports, and such summaries thereof, as may be required pursuant
          to the Trust Indenture Act at the times and in the manner
          provided pursuant to such Act; provided, that any such
          information, documents or reports required to be filed with the
          Commission pursuant to Section 13 or 15(d) of the Securities
          Exchange Act of 1934, as amended, shall be filed with the Trustee
          within 15 days after the same is so required to be filed with the
          Commission.






                                    - 2 -


                                     ARTICLE I-2

                                    Security Forms

                    SECTION I-201.  Notation.  Securities issued upon any
          registration of transfer or exchange of Securities shall be
          imprinted by the Trustee with the following notation:

                    Allegheny Teledyne Incorporated, a Delaware
                    corporation, has guaranteed the due and punctual
                    payment of the principal of and premium, if any, and
                    interest on this Security, and the holder of this
                    Security is entitled to the benefits of such guarantee. 
                    Reference is hereby made to the First Supplemental
                    Indenture dated as of August 15, 1996, copies of which
                    are on file with the Trustee, for the precise terms of
                    the guarantee therein made. 

                    SECTION I-202.  New Securities.  If the Company shall
          so determine, new Securities so modified as to conform, in the
          opinion of the Trustee and the Company, to this First
          Supplemental Indenture may be prepared and executed by the
          Company and authenticated and delivered by the Trustee in
          exchange for Outstanding Securities, instead of being imprinted
          as hereinabove provided.  

                                     ARTICLE I-3

                              Representation by Company

                    SECTION I-301.  The Company represents that immediately
          after the effective date of the Merger, no Event of Default, and
          no event which, after notice or lapse of time or both, would
          become an Event of Default, has happened and is continuing.

                                     ARTICLE I-4

                                  General Provisions

                    SECTION I-401.  Recitals.  The recitals contained
          herein shall be taken as the statements of the Company, and the
          Trustee assumes no responsibility for their correctness.  The
          Trustee makes no representations as to validity or sufficiency of
          this First Supplemental Indenture.

                    SECTION I-402.  Definitions.  Terms used in this First
          Supplemental Indenture which are defined in the Indenture and not
          otherwise defined herein shall have the respective meanings set
          forth in the Indenture.

                    SECTION I-403.  Notices, Etc., to Trustee and
          Guarantor.  Any Act of Holders or other document provided or

                                        - 3 -

          permitted by the Indenture or this First Supplemental Indenture
          to be made upon, given or furnished to, or filed with, 

                    (1)  the Trustee by the Guarantor shall be sufficient
               for every purpose hereunder if made, given, furnished or
               filed in writing to or with the Trustee at its Corporate
               Trust Office, Attention: Institutional Trust Group,
               including via facsimile transmission to (718) 242-5886, or

                    (2)  the Guarantor by the Trustee or by any Holder
               shall be sufficient for every purpose hereunder if in
               writing and mailed, first-class postage prepaid, to the
               Guarantor addressed to it, Attention: Corporate Secretary,
               at the address of its principal executive offices specified
               in the first paragraph of this instrument or at any other
               address previously furnished in writing to the Trustee by
               the Guarantor or via facsimile transmission to (412) 394-
               3010.

                    SECTION I-404.  Conflict with Trust Indenture Act.  If
          any provision hereof limits, qualifies or conflicts with a
          provision of the Trust Indenture Act that is required under such
          Act to be a part of and govern this First Supplemental Indenture,
          the latter provision shall control.  If any provision of this
          First Supplemental Indenture modifies or excludes any provision
          of the Trust Indenture Act that may be so modified or excluded,
          the latter provision shall be deemed to apply to this First
          Supplemental Indenture only as so modified or excluded, as the
          case may be.

                    SECTION I-405.  Effect of Headings.  The Article and
          Section headings herein are for convenience only and shall not
          affect the construction thereof.

                    SECTION I-406.  Successors and Assigns.  All covenants
          and agreements in this First Supplemental Indenture by the
          Guarantor shall bind or inure to the benefit of its successors
          and assigns, whether so expressed or not.

                    SECTION I-407.  Separability Clause.  In case any
          provision in this First Supplemental Indenture or in the
          Securities shall be invalid, illegal or unenforceable, the
          validity, legality and enforceability of the remaining provisions
          shall not in any way be affected or impaired thereby.

                    SECTION I-408.  Benefits of First Supplemental
          Indenture.  Nothing in this First Supplemental Indenture or in
          the Securities, express or implied, shall give to any Person,
          other than the parties hereto and their successors hereunder, any
          Security Registrar, any Paying Agent, any Authenticating Agent
          and the Holders, any benefit or any legal or equitable right,
          remedy or claim under this First Supplemental Indenture.

                                        - 4 -

                    SECTION I-409.  Governing Law.  This First Supplemental
          Indenture shall be governed by and construed in accordance with
          the laws of the jurisdiction which govern the Indenture and its 
          construction.

                    SECTION I-410.  Indenture Confirmed.  The Indenture,
          except as herein amended, supplemented or modified, is in all
          respects ratified and confirmed by this First Supplemental
          Indenture, and the provisions of this First Supplemental
          Indenture shall be deemed to be a part of the Indenture.

                    SECTION I-411.  No Security Interest Created.  Nothing
          in this First Supplemental Indenture or in the Securities,
          express or implied, shall be construed to constitute a security
          interest under the Uniform Commercial Code or similar
          legislation, as now or hereafter enacted and in effect in any
          jurisdiction where property of the Guarantor or its Subsidiaries
          is or may be located.

                    SECTION I-412.  Limitation on Individual Liability.  No
          recourse under or upon any obligation, covenant or agreement
          contained in this First Supplemental Indenture or in any
          Security, or for any claim based thereon or otherwise in respect
          thereof, shall be had against any incorporator, stockholder,
          officer or director, as such, past, present or future, of the
          Guarantor or any successor Person, either directly or through the
          Guarantor, whether by virtue of any constitution, statute or rule
          of law, or by the enforcement of any assessment or penalty or
          otherwise; it being expressly understood that this First
          Supplemental Indenture and the obligations issued hereunder are
          solely corporate obligations, and that no such personal liability
          whatever shall attach to, or is or shall be incurred by, the
          incorporators, shareholders, officers or directors, as such, of
          the Guarantor or any successor Person, or any of them, because of
          the creation of the indebtedness hereby authorized, or under or
          by reason of the obligations, covenants or agreements contained
          in this First Supplemental Indenture or in any Security or
          implied therefrom; and that any and all such personal liability
          of every name and nature, either at common law or in equity or by
          constitution or statute, of, and any and all such rights and
          claims against, every such incorporator, shareholder, officer or
          director, as such, because of the creation of the indebtedness
          hereby authorized, or under or by reason of the obligations,
          covenants or agreements contained in this First Supplemental
          Indenture or in any Security or implied therefrom, are hereby
          expressly waived and released as a condition of, and as a
          consideration for, the execution of this First Supplemental
          Indenture and the issuance of such Security. 

                    SECTION I-413.  Date.  The date of this First
          Supplemental Indenture is intended as and for a date for the
          convenient identification of this instrument and is not intended

                                        - 5 -

          to indicate that this instrument was executed or delivered on
          said date, it being hereby provided and stipulated that this
          instrument may be executed and delivered either on said date or
          before or after said date, and is, in fact, executed and
          delivered on the dates of the respective certificates of
          acknowledgement hereto attached.

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                                         * * *

                    This instrument may be executed in any number of
          counterparts, each of which when so executed shall be deemed to
          be an original, but all such counterparts shall together
          constitute but one and the same instrument.

                    IN WITNESS WHEREOF, the parties hereto have caused this
          First Supplemental Indenture to be duly executed, and their
          respective corporate seals to be hereunto affixed and attested,
          all as of the day and year first above written.

          ATTEST:                           ALLEGHENY LUDLUM CORPORATION




          /s/ Jon D. Walton                 By:/s/ James L. Murdy         
          ------------------------------       ----------------------------
          Name:  Jon D. Walton                 Name:  James L. Murdy       
          Title: Vice President -General       Title: Senior Vice President
                  Counsel & Secretary                  -Finance & Chief 
                                                         Financial Officer
          (Corporate Seal)


          ATTEST:                           ALLEGHENY TELEDYNE INCORPORATED




          /s/ Jon D. Walton                 By:/s/ James L. Murdy         
          ------------------------------       ----------------------------
          Name:  Jon D. Walton                 Name:  James L. Murdy       
          Title: Vice President -General       Title: Senior Vice President
                  Counsel & Secretary                  -Finance & Chief 
                                                         Financial Officer
          (Corporate Seal)


          ATTEST:                            THE CHASE MANHATTAN BANK,
                                             AS TRUSTEE




          /s/ Gemmel Richards                By: /s/ J. D. Heaney        
          ------------------------------        ---------------------------
          Name:  Gemmel Richards                Name:  James D. Heaney
          Title: Assistant Secretary            Title: Vice President 

          (Corporate Seal)

                                           - 7 -


                                      ACKNOWLEDGMENTS

          COMMONWEALTH OF PENNSYLVANIA    )
                                          )
          COUNTY OF ALLEGHENY             )

                    BEFORE ME, the undersigned authority, on this day personally
          appeared JAMES L. MURDY, the Senior Vice President-Finance and Chief
          Financial Officer of ALLEGHENY LUDLUM CORPORATION, known to me to be
          the person whose name is subscribed to the above and foregoing
          instrument of writing, and acknowledged to me that he executed the
          same for the purposes and consideration therein expressed, in the
          capacity therein stated, and as the act and deed of said corporation;
          and, being by me duly sworn, did depose and say that he resides at
          Upper St. Clair, that he is the Senior Vice President-Finance and
          Chief Financial Officer of said corporation, that he knows the seal of
          said corporation, that the seal affixed to said instrument is such
          corporate seal, that it was so affixed by authority of the Board of
          Directors of said corporation, and that he signed his name thereto by
          like authority.

               GIVEN UNDER MY HAND AND SEAL OF OFFICE, this 15th day of August,
          1996.



                                             /s/ Mary Beth Luksik               
                                             -------------------------------
                                             Notary Public

                                             My commission expires on:  
                                             June 8, 1998


          COMMONWEALTH OF PENNSYLVANIA    )
                                          )
          COUNTY OF ALLEGHENY             )

                    BEFORE ME, the undersigned authority, on this day personally
          appeared JAMES L. MURDY, the Senior Vice President and Chief Financial
          Officer of ALLEGHENY TELEDYNE INCORPORATED, known to me to be the
          person whose name is subscribed to the above and foregoing instrument
          of writing, and acknowledged to me that he executed the same for the
          purposes and consideration therein expressed, in the capacity therein
          stated, and as the act and deed of said corporation; and, being by me
          duly sworn, did depose and say that he resides at Upper St. Clair,
          that he is the Senior Vice President and Chief Financial Officer of
          said corporation, that he knows the seal of said corporation, that the
          seal affixed to said instrument is such corporate seal, that it was so
          affixed by authority of the Board of Directors of said corporation,
          and that he signed his name thereto by like authority.

               GIVEN UNDER MY HAND AND SEAL OF OFFICE, this 15th day of August,
          1996.



                                             /s/ Mary Beth Luksik              
                                             -------------------------------
                                             Notary Public

                                             My commission expires on:  
                                                       June 8, 1998

          THE STATE OF NEW YORK)
                               )
          COUNTY OF NEW YORK   )

                    BEFORE ME, the undersigned authority, on this day personally
          appeared James D. Heaney, the Vice President of THE CHASE MANHATTAN
          BANK, known to me to be the person whose name is subscribed to the
          above and foregoing instrument of writing, and acknowledged to me that
          he executed the same for the purposes and consideration therein
          expressed, in the capacity therein stated, and as the act and deed of
          said corporation; and, being by me duly sworn, did depose and say that
          he resides at 18 Choate Ct., Langhorne, PA  19047, that he is a Vice
          President of said corporation, that he knows the seal of said
          corporation, that the seal affixed to said instrument is such
          corporate seal, that it was so affixed by authority of the Board of
          Directors of said corporation, and that he signed his name thereto by
          like authority.


                    GIVEN UNDER MY HAND AND SEAL OF OFFICE this 12th day of
          August, 1996.


                                             /s/ Della K. Benjamin       
                                             -------------------------------
                                             Notary Public in and for


                                             My commission expires on:  
                                                  April 30, 1997