<PAGE>   1
                                                                     Exhibit 3.1

                             CERTIFICATE OF AMENDED
                           ARTICLES OF INCORPORATION
                                       OF
                         AMCAST INDUSTRIAL CORPORATION
                         -----------------------------

     The undersigned, Leo W. Ladehoff and Thomas G. Amato, being respectively,
the Chief Executive Officer and Secretary of AMCAST INDUSTRIAL CORPORATION (the
"Corporation"), a corporation for profit organized under the Ohio General
Corporation Law, with its principal office located in the City of Kettering,
Montgomery County, Ohio, do hereby certify that a meeting of the directors of
the Corporation was duly called and held on April 23, 1987, at which meeting a
quorum of the directors was present and acting throughout, and that at such
meeting, the directors unanimously adopted a resolution adopting new Amended
Articles of Incorporation of the Corporation to supercede and consolidate the
original Articles of Incorporation of the Corporation and all amendments thereto
as follows:

          "FIRST. The name of said Corporation shall be Amcast Industrial
     Corporation.

          SECOND. The purpose or purposes of the Corporation shall be:

          (a) To manufacture, purchase, lease, or otherwise acquire and to hold,
     own, sell, lease, or dispose of, trade in or deal in castings and other
     allied, similar or related products of every kind and description.

          (b) To engage in any lawful act or activities for which corporations
     may be formed under Section 1701.01 to 1701.98, inclusive, of the Ohio
     Revised Code.

          THIRD. The place in the State of Ohio where the Corporation's
     principal office shall be located is Kettering, Montgomery County, Ohio.

          FOURTH. The maximum number of shares which the Corporation is
     authorized to have outstanding is 16,000,000 shares which shall be
     classified as follows:

               1,000,000 Preferred Shares without par value (hereinafter called
          "Preferred Shares"); and

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          15,000,000 Common Shares without par value (hereinafter called
          "Common Shares").

          Section 1. The express terms and provisions of the Preferred Shares
     are as follows:

          1.1 Preferred Shares may be issued in series from time to time. Within
     the limitations and restrictions set forth in this Article FOURTH, the
     Board of Directors is expressly authorized, at one time or from time to
     time, to adopt amendments to the Articles of Incorporation in respect of
     any authorized and unissued Preferred Shares to fix or alter the division
     of such shares into series, the designation and number of shares of each
     series, the dividend rates, redemption rights, redemption prices,
     liquidation prices, sinking fund requirements, conversion rights, and
     restrictions on issuance of shares of the same series or of any other class
     or series. The express terms and provisions of Preferred Shares of
     different series shall be identical except that there may be variations in
     respect of any or all of the particulars hereinbefore set forth in this
     subsection 1.1. In case the stated dividends or the amounts payable on
     dissolution, liquidation, or sale of assets of the Corporation are not paid
     in full, all Preferred Shares of all series shall participate ratably in
     the payment of dividends, including accumulations, if any, in proportion to
     the sums which would be payable thereon if all dividends thereon were paid
     in full, and, in any distribution of assets other than by way of dividends,
     in proportion to the same which would be payable on such distribution if
     all sums payable thereon to holders of Preferred Shares were discharged in
     full.

          1.2 The holders of Preferred Shares shall be entitled to receive when
     and as declared out of the surplus of the Corporation, subject to any
     limitations prescribed by statute, cash dividends at the respective rates
     and on the respective dates fixed by the Board of Directors for the shares
     of the several series of Preferred Shares, and no more. Dividends on each
     Preferred Share shall be cumulative from the date fixed therefor by the
     Board of Directors.

          1.3 Except as may be otherwise expressly provided in this Article
     FOURTH, the Corporation 



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     shall have the right to redeem the Preferred Shares of any one or more
     series at any time, either in whole or in such portions, as from time to
     time, the Board of Directors may determine, upon the payment to the
     respective holders thereof of the "General Redemption Price" thereof. The
     General Redemption Price for shares of each series shall be an amount equal
     to the sum of (a) the redemption price fixed by the Board of Directors for
     the shares of such series prior to the initial issuance of the first shares
     of such series; and (b) an amount equivalent to all accumulated and unpaid
     dividends on the shares to be redeemed to the date fixed for redemption
     (hereinafter referred to as the "Redemption Date"), whether or not such
     dividends shall have been earned or declared. In lieu of such payment the
     Corporation may deposit the General Redemption Price of the shares to be
     redeemed on or prior to the Redemption Date with such responsible bank or
     trust company as may be designated by the Board of Directors, in trust, for
     payment on or after the date of such deposit (without awaiting the
     Redemption Date) to the holders of Preferred Shares then to be redeemed. If
     less than the whole amount of outstanding Preferred Shares of any
     particular series shall be redeemed at any time, the shares thereof to be
     redeemed shall be selected by lot.

          Notice of any such redemption, in whole or in part, and of any such
     deposit made or to be made of such General Redemption Price, shall be
     mailed to each holder of Preferred Shares so to be redeemed, at his address
     registered with the Corporation, not less than thirty days prior to the
     Redemption Date, and, if less than all of the said shares owned by such
     shareholders are to be redeemed, the notice shall specify the number of
     shares thereof which are to be redeemed. Such notice having been so given,
     or irrevocable written authority to the depositary having been given at the
     time of making the deposit provided for herein forthwith to give such
     notice, all rights of the respective holders of the said shares as
     shareholders of the Corporation by reason of the ownership of such shares,
     except the right to receive the General Redemption Price of such shares
     upon presentation and surrender of their respective certificates
     representing the said shares, shall cease from and after the Redemption
     Date (unless default shall be made by the Corporation in providing monies
     for the payment of the General Redemption Price), or, if 



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     the General Redemption Price shall have been deposited on or prior to the
     Redemption Date as above permitted, from and after the date of such
     deposit; provided, however, that in lieu of the right to receive the
     General Redemption Price, any rights of conversion or exchange may be
     exercised up to the close of business on the Redemption Date. If after such
     deposit any Preferred Shares so called shall be so converted or exchanged,
     the amount theretofore deposited with the depositary for the redemption
     thereof shall forthwith be paid over by it to the Corporation. Any other
     monies so deposited which shall remain unclaimed by the holders of
     Preferred Shares so called for redemption at the end of two years after the
     Redemption Date shall be paid by such depositary to the Corporation, after
     which the holders of such Preferred Shares shall look only to the
     Corporation for payment of the General Redemption Price thereof, without
     interest.

          1.4 Upon the dissolution, liquidation or sale of all or substantially
     all the assets of the Corporation, the holders of Preferred Shares shall be
     entitled to receive the following sums, before any payment shall be made to
     the holders of Common Shares with respect to payment upon dissolution,
     liquidation or sale of assets:

          (a)  in case of any involuntary dissolution or liquidation or forced
               sale of all or substantially all the assets of the Corporation,
               each Preferred Share of each series shall be entitled to receive
               the amount fixed for such contingency by the Board of Directors
               for the shares of such series prior to the issuance of the first
               shares of such series, together with a sum, whether or not earned
               or declared, equivalent to all accumulated and unpaid dividends
               thereon to the date of such payment; or

          (b)  in case of any voluntary dissolution or liquidation or voluntary
               sale of all or substantially all the assets of the Corporation,
               each Preferred Share of each series shall be entitled to receive
               the amount fixed for such contingency by the Board of 


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               Directors for the shares of such series prior to the initial
               issuance of the first shares of such series, together with a sum,
               whether or not earned or declared, equivalent to all accumulated
               and unpaid dividends thereon to the date of such payment.

          After all sums payable on the Preferred Shares as herein provided upon
     a particular contingency shall have been paid in full, but not prior
     thereto, the Common Shares shall be entitled to payment of all other sums
     then distributable. For the purposes of this subsection 1.4, a
     consolidation or merger of the Corporation with or into any other
     corporation, or a consolidation or merger of any other corporation with or
     into the Corporation shall not be deemed a dissolution, liquidation or sale
     of assets.

          1.5 The holders of Preferred Shares shall be entitled to one vote for
     each Preferred Share held by them respectively.

          1.6 So long as any of the Preferred Shares shall remain outstanding,
     no dividend (other than dividends payable in Common Shares) shall be paid,
     nor shall any distribution (by purchase, redemption, payment to any sinking
     fund, or otherwise, other than stock splits) be made, on any of the Common
     Shares unless:

          (a)  all dividends on all outstanding Preferred Shares shall have been
               paid and full dividends thereon for the then current quarterly
               dividend period shall have been declared and a sum sufficient for
               the payment thereof set apart therefor; and

          (b)  the Corporation shall not be in arrears in respect of any sinking
               fund obligation in respect of any series of Preferred Shares.

          1.7 Preferred Shares acquired by the Corporation through the exercise
     by the holders thereof of any conversion privilege shall not be reissued
     except as hereinafter provided. Such shares and any other Preferred Shares
     acquired otherwise than through the operation of any sinking fund and not
     used to reduce the amount of any

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     sinking fund installment shall, upon compliance with such provisions of law
     relating to the retirement of shares as may be applicable, have the status
     of authorized and unissued Preferred Shares which are unclassified into any
     series. Preferred Shares acquired by the Corporation through the operation
     of any sinking fund or which have been used to reduce the amount of any
     sinking fund installment shall be cancelled and not reissued, and the
     Corporation shall from time to time take appropriate corporate action to
     reduce the authorized number of Preferred Shares accordingly.

          Section 2. The express terms and provisions of the Common Shares are
     as follows:

          2.1 The rights and preferences of the Common Shares shall be subject
     in all respects to the rights and preferences of the Preferred Shares in
     the manner and to the extent provided in this Article FOURTH.

          2.2 The Common Shares shall rank junior to the Preferred Shares with
     respect to the payment of dividends. Out of the assets of the Corporation
     available for dividends remaining after there shall have been paid or
     declared and set apart for payment full dividends on the Preferred Shares,
     and subject to the restrictions or limitations contained in the express
     terms and provisions of any series of Preferred Shares, dividends may be
     declared and paid upon the Common Shares, but only when and as determined
     by the Board of Directors.

          2.3 The Common Shares shall rank junior to the Preferred Shares with
     respect to payment upon dissolution, liquidation or sale of the assets of
     the Corporation. Upon the dissolution, liquidation or sale of all or
     substantially all the assets of the Corporation, after there shall have
     been paid to or set apart for holders of the Preferred Shares the full
     preferential amounts to which they are entitled, the holders of Common
     Shares shall be entitled to receive pro rata all of the remaining assets of
     the Corporation available for distribution to its shareholders.

          2.4 The holders of Common Shares shall be entitled to one vote for
     each Common Share held by them respectively.

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          Section 3. No shareholder of the Corporation shall have the right to
     vote cumulatively in the election of directors of the Corporation.

          FIFTH. The Corporation, through its Board of Directors, shall have the
     right and power to purchase any of its outstanding shares of stock at such
     price and upon such terms as may be agreed upon between the Corporation and
     the selling shareholder or shareholders.

          SIXTH. Notwithstanding any provision of the Ohio Revised Code now or
     hereafter in force providing for any action for the vote, consent, waiver,
     or release of the holders of shares entitling them to exercise two-thirds,
     or any other proportion, of the voting power of the Corporation or of any
     class or classes of shares thereof, such action, unless otherwise expressly
     required by statute or by these Amended Articles of Incorporation, may be
     taken by the vote, consent, waiver, or release of the holders of shares
     entitling them to exercise a majority of the voting power of the
     Corporation or of such class or classes .

          SEVENTH. Notwithstanding the foregoing, the affirmative vote of the
     holders of shares entitling them to exercise at least four-fifths of the
     voting power of the Corporation shall be required:

          (a)  To approve (i) the sale, exchange, lease, transfer, or other
               disposition by the Corporation of all, or substantially all, of
               its assets or business to a related corporation or an affiliate
               of a related corporation, or (ii) the consolidation of the
               Corporation with or its merger into a related corporation or an
               affiliate of a related corporation, or (iii) the merger into the
               Corporation of a related corporation, or (iv) a combination or
               majority share acquisition in which the Corporation is the
               acquiring corporation and its voting shares are issued or
               transferred to a related corporation or an affiliate of a related
               corporation or to shareholders of a related corporation or an
               affiliate of a related corporation; or

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          (b)  to approve any agreement, contract, or other arrangement with a
               related corporation providing for any of the transactions
               described in subparagraph (a) above.

          For the purpose of this Article SEVENTH, (i) a "related corporation"
     in respect of a given transaction shall be any corporation which, together
     with its affiliates and associated persons, owns of record or beneficially,
     directly or indirectly, more than 5% of the shares of any class of
     outstanding shares of the Corporation entitled to vote upon such
     transaction, as of the record date used to determine the shareholders of
     the Corporation entitled to vote upon such transaction; (ii) an "affiliate"
     of a related corporation shall be any individual, joint venture, trust,
     partnership, or corporation which, directly or indirectly through one or
     more intermediaries, controls, or is controlled by, or is under common
     control with the related corporation; (iii) an "associated person" of a
     related corporation shall be any officer or director or any beneficial
     owner, directly or indirectly, of 10% or more of any class of equity
     security of such related corporation or any of its affiliates; (iv) the
     terms "combination", or "majority share acquisition" and "acquiring
     corporation" shall have the same meaning as that contained in Section 1701
     of the Ohio General Corporation Law or any similar provision hereafter
     enacted.

          The determination of the Board of Directors of the Corporation, based
     on information known to the Board of Directors and made in good faith,
     shall be conclusive as to whether any corporation is a related corporation
     as defined in this Article SEVENTH.

          The provisions of this Article SEVENTH shall not be applicable to (i)
     any merger or consolidation of the Corporation with or into any other
     corporation, or any sale or lease of all, or substantially all, of the
     assets of the Corporation to, or any sale or lease to the Corporation, or
     any subsidiary thereof, in exchange for securities of the Corporation of
     any assets of, any corporation if the Board of Directors of the Corporation
     shall by resolution have approved a memorandum of understanding with such
     other corporation with

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     respect to and substantially consistent with such transaction prior to the
     time that such other corporation shall have become a holder of more than
     20% of the outstanding shares of stock of the Corporation entitled to vote
     in elections of Directors; or (ii) any merger or consolidation of the
     Corporation with, or any sale or lease to the Corporation, or any
     subsidiary thereof, of any of the assets of, any corporation of which a
     majority of the outstanding shares of all classes of stock entitled to vote
     in elections of Directors is owned of record or beneficially by the
     Corporation and its subsidiaries.

          No amendment to the Articles of Incorporation of the Corporation shall
     amend, alter, change, or repeal any of the provisions of this Article
     SEVENTH, unless the amendment effecting such amendment, alteration, change,
     or repeal shall receive the affirmative vote or consent of the holders of
     shares entitling them to exercise at least four-fifths of the voting power
     of the Corporation.

          EIGHTH. No holder of shares of the Corporation of any class, as such,
     shall have any preemptive right to purchase or subscribe for shares of the
     Corporation, of any class, or other securities of the Corporation, of any
     class, whether now or hereafter authorized.

     IN WITNESS WHEREOF, the undersigned, being respectively the Chief Executive
Officer and Secretary of the Corporation, acting for and on behalf of the
Corporation, have executed this Certificate and caused the seal of the
Corporation to be affixed hereto this 12th day of June, 1987.

                              /s/ Leo W. Ladehoff
                              --------------------------------
                              Leo W. Ladehoff, Chief Executive

                              /s/ Thomas G. Amato
                              --------------------------------
                              Thomas G. Amato, Secretary

(SEAL)

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                          CERTIFICATE OF AMENDMENT TO
                       AMENDED ARTICLES OF INCORPORATION
                                       OF
                         AMCAST INDUSTRIAL CORPORATION
                         -----------------------------

     The undersigned, Leo W. Ladehoff and Thomas G. Amato, being respectively,
the Chairman of the Board and the Secretary of AMCAST INDUSTRIAL CORPORATION
(the "Corporation"), an Ohio corporation, do hereby certify that at a meeting of
the directors of the Corporation duly called and held on February 24, 1988, the
following resolution was unanimously adopted:

     NOW, THEREFORE BE IT RESOLVED, that pursuant to the authority vested in the
Board of Directors in accordance with the provisions of Article Fourth of its
Amended Articles of Incorporation, such Article Fourth hereby is amended to set
forth the designation and number of a new series of Preferred Shares and the
powers, preferences, and relative, participating, optional, and other special
rights and the qualifications, limitations, or restrictions thereof, as follows:

     Section 4. Series A Preferred Shares.

     4.1. DESIGNATION AND AMOUNT. There shall be a series of the Preferred
Shares of the Corporation which shall be designated as the "Series A Preferred
Shares," without par value, and the number of such shares shall be 300,000.

     4.2. DIVIDENDS AND DISTRIBUTIONS.

     (A) Subject to the prior and superior rights of the holders of any shares
of any classes of preferred shares of the Corporation ranking prior and superior
to the Preferred Shares with respect to dividends, the holders of the Preferred
Shares in preference to the holders of Common Shares of the Corporation (the
"Common Shares"), and any other junior shares, shall be entitled to receive,
when, as and if declared by the Board of Directors out of funds legally
available for the purpose, quarterly dividends payable in cash on the last day
of March, June, September, and December in each year (or, in each case, if not a
date on which the Corporation is open for business, the next date on which the
Corporation is so open) (each such date being referred to herein as a "Quarterly
Dividend Payment Date"), commencing on the first Quarterly Dividend Payment Date



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after the first issuance of a Preferred Share or fraction thereof, in an amount
per share (rounded to the nearest cent) equal to the greater of (a) $11.00, or
(b) subject to the provision for adjustment hereinafter set forth, 100 times the
aggregate per share amount of all cash dividends, and 100 times the aggregate
per share amount (payable in kind) of all non-cash dividends or other
distributions other than a dividend payable in Common Shares or a subdivision of
the outstanding Common Shares (by reclassification or otherwise), declared on
the Common Shares, since the immediately preceding Quarterly Dividend Payment
Date, or, with respect to the first Quarterly Dividend Payment Date, since the
first issuance of any share or fraction of a Preferred Share. In the event the
Corporation at any time after February 24, 1988 (the "Rights Declaration Date")
(i) declares any dividend on Common Shares payable in Common Shares, (ii)
subdivides the outstanding Common Shares, or (iii) combines the outstanding
Common Shares into a smaller number of shares (all of which are hereinafter
referred to as "Common Share Adjustments"), then in each such case the amount to
which holders of the Preferred Shares were entitled immediately prior to such
event under clause (b) of the preceding sentence shall be adjusted by
multiplying such amount by a fraction the numerator of which is the number of
Common Shares outstanding immediately after such event and the denominator of
which is the number of Common Shares that were outstanding immediately prior to
such event (such fraction is hereinafter referred to as the "Adjustment 
Number").

     (B) The Corporation shall declare a dividend or distribution on the
Preferred Shares as provided in paragraph (A) above immediately after it
declares a dividend or distribution on the Common Shares (other than a dividend
payable in Common Shares); provided that, in the event no dividend or
distribution shall have been declared on the Common Shares during the period
between any Quarterly Dividend Payment Date and the next subsequent Quarterly
Dividend Payment Date, a dividend of $11.00 per share on the Preferred Shares
shall nevertheless be payable on such subsequent Quarterly Dividend Payment
Date.

     (C) Dividends shall begin to accrue and be cumulative on the outstanding
Preferred Shares from the Quarterly Dividend Payment Date next preceding the
date of issue of such Preferred Shares, unless the date of issue of such shares
is prior to the record date for the first Quarterly Dividend Payment Date, in
which case dividends on such shares shall begin to accrue from the date of issue
of such shares, or unless the date of issue is a Quarterly

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Dividend Payment Date or is a date after the record date for the determination
of holders of Preferred Shares entitled to receive a quarterly dividend and
before such Quarterly Dividend Payment Date in either of which events such
dividends shall begin to accrue and be cumulative from such Quarterly Dividend
Payment Date. Accrued but unpaid dividends shall not bear interest. Dividends
paid on the Preferred Shares in an amount less than the total amount of such
dividends at the time accrued and payable on such shares shall be allocated pro
rata on a share-by-share basis among all such shares at the time outstanding.
The Board of Directors may fix a record date for the determination of holders of
Preferred Shares entitled to receive payment of a dividend or distribution
declared thereon, which record date shall be no more than 30 days prior to the
date fixed for the payment thereof.

     4.3. VOTING RIGHTS. The holders of the Preferred Shares shall have the
following voting rights:

     (A) Each holder of a Preferred Share shall have one vote on all matters
submitted to a vote of the shareholders of the Corporation.

     (B) Except as otherwise provided herein or by law, the holders of the
Preferred Shares and the holders of Common Shares shall vote together as one
class on all matters submitted to a vote of shareholders of the Corporation.

     (C) Except as set forth herein, holders of the Preferred Shares shall have
no special voting rights and their consent shall not be required (except to the
extent they are entitled to vote with holders of Common Shares as set forth
herein) for taking any corporate action.

     4.4. CERTAIN RESTRICTIONS.

     (A) So long as any of the Preferred Shares remain outstanding, no dividend
(other than dividends payable in Common Shares) shall be paid, nor shall any
distribution (by purchase, redemption, payment to any sinking fund, or
otherwise, other than stock splits) be made, on any of the Common Shares unless
all dividends on all outstanding Preferred Shares shall have been paid and full
dividends thereon for the then current quarterly dividend period shall have been
declared and a sum sufficient for the payment thereof set apart therefor.

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     (B) The Corporation shall not permit any subsidiary of the Corporation to
purchase or otherwise acquire for consideration any shares of the Corporation
unless the Corporation could, under paragraph (A) of this Section 4.4, purchase
or otherwise acquire such shares at such time and in such manner.

     4.5. REACQUIRED SHARES. Any Preferred Shares purchased or otherwise
acquired by the Corporation in any manner whatsoever shall be retired and
cancelled promptly after the acquisition thereof. Unless otherwise prohibited by
the Corporation's Amended Articles of Incorporation, all such shares shall upon
their cancellation become authorized but unissued Preferred Shares and may be
reissued as part of a new series of Preferred Shares, subject to the conditions
and restrictions on issuance set forth herein.

     4.6. LIQUIDATION, DISSOLUTION, OR WINDING UP.

     (A) Upon any liquidation (voluntary or otherwise), dissolution, or winding
up of the Corporation, no distribution shall be made to the holders of shares
ranking junior (either as to dividends or upon liquidation, dissolution, or
winding up) to the Preferred Shares unless, prior thereto, the holders of
Preferred Shares shall have received $4,000 per share, plus an amount equal to
accrued and unpaid dividends and distributions thereon, whether or not declared,
to the date of such payment (the "Liquidation Preference"). Following the
payment of the full amount of the Liquidation Preference, no additional
distributions shall be made to the holders of Preferred Shares unless, prior
thereto, the holders of Common Shares shall have received an amount per share
(the "Common Payment") equal to the quotient obtained by dividing (i) the
Liquidation Preference by (ii) 100 (subject to the provision for adjustment set
forth in subparagraph C). Following the payment of the full amount of the
Liquidation Preference and the Common Payment in respect of all outstanding
Preferred Shares and Common Shares, respectively, holders of Preferred Shares
and holders of Common Shares shall receive their ratable and proportionate share
of the remaining assets to be distributed in the ratio of 100 to 1 with respect
to such Preferred Shares and Common Shares, on a per share basis, respectively
(subject to the provision for adjustment set forth in subparagraph C).

     (B) In the event there are not sufficient assets available to permit
payment in full of the Liquidation Preference and the liquidation preferences of
all other classes of preferred shares, if any, which rank on a parity with the
Preferred Shares, then such remaining assets shall

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