<PAGE>   1
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM 10-Q

[X] Quarterly report pursuant to Section 13 or 15(d) of the Securities Exchange
    Act of 1934
    For the quarterly period ended June 30, 1998, or

[ ] Transition report pursuant to Section 13 or 15(d) of the Securities
    Exchange Act of 1934
    For the transition period from       to             

                         Commission File Number 0-17028

                               IRONTON IRON, INC.
             (Exact name of registrant as specified in its charter)

                      OHIO                              31-1117407
          (State or other jurisdiction of              (IRS Employer 
          incorporation or organization)             Identification No.)

            5445 Corporate Drive, Suite 200, Troy Michigan  48098-2683
              (Address of principal executive offices)      (Zip code)

                                 (248) 952-2500
              (Registrant's telephone number, including area code)

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days. Yes   X     No
                                       -----      -----

At August 8, 1998 there were 23,000 shares of Common Stock, no par value,
outstanding.



<PAGE>   2
                         PART I - FINANCIAL INFORMATION

ITEM 1. FINANCIAL STATEMENTS

                               Ironton Iron, Inc.

                        Interim Condensed Balance Sheets



<TABLE>
<CAPTION>
                                            June 30,      December 31,
                                              1998            1997
                                         --------------   ------------
                                          (Unaudited)
                                            (in thousands of dollars)
<S>                                        <C>               <C>
Assets
Current assets:
   Cash                                      $    63        $    21
   Accounts receivable:
       Trade, less allowance for
         doubtful accounts of
         $375 in 1998 and $300 in 1997         7,136          5,255
       Other                                     168            262
   Inventories                                 3,255          2,578
   Other current assets                           76            137
                                             -------        -------
Total current assets                          10,698          8,253

Property, plant and equipment:                                                 
   Land                                          295            295
   Building and improvements                   5,858          5,360
   Machinery and equipment                    30,042         28,670
   Construction in progress                      541          1,548
                                             -------        -------
                                              36,736         35,873

   Less accumulated depreciation              21,111         19,778
                                             -------        -------
Net property, plant and equipment             15,625         16,095

Other non current assets                           9             18
                                             -------        -------
                                             $26,332        $24,366
                                             =======        =======
</TABLE>



                                       2




<PAGE>   3
                               Ironton Iron, Inc.

                        Interim Condensed Balance Sheets


<TABLE>
<CAPTION>
                                            June 30,     December 31,
                                              1998          1997
                                         --------------  -------------
                                          (Unaudited)
                                            (in thousands of dollars)
<S>                                           <C>           <C>
Liabilities and shareholders' deficiency 
Current liabilities:
   Accounts payable                           $ 3,244       $ 2,781
   Accrued wages and benefits                   1,100         1,093
   Accrued workers' compensation                  406           597
   Other accrued liabilities                      295           373
                                              -------       -------    
Total current liabilities                       5,045         4,844

Due to affiliates                              43,606        40,309

Redeemable preferred stock                      3,448         3,389

Net shareholder's deficiency:
    Common stock                                2,000         2,000
    Additional paid-in capital                 49,523        49,523
    Accumulated deficit                       (77,290)      (75,699)
                                              -------       -------    
Net shareholder's deficiency:                 (25,767)      (24,176)
                                              -------       -------    
                                              $26,332       $24,366
                                              =======       =======    
</TABLE>



See accompanying notes.



                                       3


<PAGE>   4
                               Ironton Iron, Inc.

                     Interim Condensed Statements of Income


<TABLE>
<CAPTION>
                                   Three months ended            Six months ended
                                 June 30,      June 30,       June 30,      June 30,
                                   1998          1997           1998          1997
                                 --------      --------       --------      --------    
                                                     (Unaudited)
                                              (in thousands of dollars)

<S>                               <C>           <C>            <C>           <C>
Net sales                         $13,494       $13,395        $27,935       $25,901
Cost of sales                      14,411        13,960         29,267        27,784
                                  -------       -------        -------       -------                                               

Gross profit                         (917)         (565)        (1,332)       (1,883)

Operating income (expense):
  Corporate charges from parent      (420)         (493)          (840)         (986)
  Other operating income              129           121            279           121
                                  -------       -------        -------       -------                                               
Operating loss                     (1,208)         (937)        (1,893)       (2,748)

Interest expense                      190           128            360           236
                                  -------       -------        -------       -------                                               
Loss before income taxes and
  cumulative effect of
  accounting change                (1,398)       (1,065)        (2,253)       (2,984)
Provision for income taxes              -             -              -             -
                                  -------       -------        -------       -------                                               
Loss before cumulative effect
  of accounting change             (1,398)       (1,065)        (2,253)       (2,984)
Cumulative effect of
  accounting change                     -             -            290             -
                                  -------       -------        -------       -------                                               
Net loss                          ($1,398)      ($1,065)       ($1,963)      ($2,984)
                                  =======       =======        =======       =======   
</TABLE>

See accompanying notes.



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<PAGE>   5
                               Ironton Iron, Inc.

                   Interim Condensed Statements of Cash Flows



<TABLE>
<CAPTION>
                                              Six months ended
                                            June 30,     June 30,
                                              1998         1997
                                           ------------  ----------
                                                 (Unaudited)
                                           (in thousands of dollars)
<S>                                         <C>          <C>
Operating activities:
Net loss                                      ($1,963)    ($2,984)
Adjustments to reconcile net income to
  cash used in operating activities:
  Depreciation and amortization                 1,342       1,384
  Changes in operating assets and
   liabilities:
   Accounts receivable                         (1,787)     (2,610)
   Inventories                                   (677)       (658)
   Accounts payable and accrued
    liabilities                                   201         560
   Other assets and liabilities                    61         (99)
                                              -------     -------
Net cash used in operating activities          (2,823)     (4,407)

Investing activities:
  Additions to property, plant and
   equipment                                     (864)       (693)
  Other                                                      (370)
                                              -------     -------
Net cash used in investing activities            (864)     (1,063)

Financing activities:
  Increase in due to affiliates                 3,729       5,509
                                              -------     -------
Net cash provided by financing activities       3,729       5,509
                                              -------     -------
Net increase in cash and cash equivalents          42          39

Cash at beginning of period                        21          52
                                              -------     -------
Cash at end of period                         $    63     $    91
                                              =======     =======

</TABLE>




See accompanying notes.


                                       5


<PAGE>   6
                               Ironton Iron, Inc.

                 Notes to Interim Condensed Financial Statements

                            June 30, 1998 (Unaudited)


1. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited condensed financial statements of Ironton Iron, Inc.
("Company") have been prepared in accordance with generally accepted accounting
principles for interim financial information and with the instructions to Form
10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of
the information and footnotes required by generally accepted accounting
principles for complete financial statements. In the opinion of management, all
adjustments (consisting of normal recurring accruals) considered necessary for a
fair presentation have been included. Operating results for the six months ended
June 30, 1998 are not necessarily indicative of the results that may be expected
for the year ended December 31, 1998. For further information, refer to the
financial statements and footnotes thereto included in the Company's annual
report on Form 10-K for the year ended December 31, 1997.

Inventories

Inventories consist of the following (in thousands of dollars):


<TABLE>
<CAPTION>
                                          June 30,       December 31, 
                                            1998            1997
                                        -------------  -------------
               <S>                          <C>           <C>
               Finished goods               $  107        $   64
               Work in process                 691           376
               Raw materials                   600           554
               Supplies and patterns         1,857         1,584
                                            ------        ------     
                                            $3,255        $2,578
                                            ======        ======    
</TABLE>


Loss per Common Share

Because Intermet Corporation ("Intermet") owns all common stock of the Company,
no income or loss per common share information is included herein.



                                       6

<PAGE>   7


                               Ironton Iron, Inc.

           Notes to Interim Condensed Financial Statements (continued)

                            June 30, 1998 (Unaudited)


2. Inventory Change in Accounting Method

Effective January 1, 1998, the Company changed its method of accounting for
spare parts used in its equipment. Previously, the Company expensed these parts
in the period during which they were purchased but will now inventory the parts
and charge them to expense in the period in which they are used. This method is
consistent with prevailing industry practice, as well as with the policy
followed by Intermet's other foundry subsidiaries. In management's opinion, this
method of accounting results in better matching of costs and related revenues.
The cumulative effect of this change decreases the net loss $290,000 for the six
months ended June 30, 1998. Proforma results for the six-month period ended June
30, 1997 would not have been materially different from historical results had
this new method been employed at that time.

3. Comprehensive Income

During 1997, the Financial Accounting Standards Board issued Statement of
Financial Accounting Standards No. 130, "Reporting Comprehensive Income", which
the Company adopted as of January 1, 1998. Statement 130 establishes new rules
for reporting and display of comprehensive income and its components. The
Company's comprehensive losses for the quarters and six months ended June 30,
1998 and 1997 are the same as the net losses reported, respectively.

ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
        RESULTS OF OPERATIONS

THIS MANAGEMENT'S DISCUSSION AND ANALYSIS OF MATERIAL CHANGES IN FINANCIAL
CONDITION AND MATERIAL CHANGES IN RESULTS OF OPERATIONS CONTAINS FORWARD-LOOKING
STATEMENTS WITHIN THE MEANING OF THE PRIVATE SECURITIES LITIGATION REFORM ACT OF
1995. WHEN USED IN THIS SECTION, THE WORDS "ANTICIPATE," "BELIEVE," "ESTIMATE"
AND "EXPECT" AND SIMILAR EXPRESSIONS ARE GENERALLY INTENDED TO IDENTIFY
FORWARD-LOOKING STATEMENTS. READERS ARE CAUTIONED THAT ANY FORWARD-LOOKING
STATEMENTS, INCLUDING STATEMENTS REGARDING THE INTENT, BELIEF OR CURRENT
EXPECTATIONS OF THE COMPANY OR ITS MANAGEMENT, ARE NOT GUARANTEES OF FUTURE
PERFORMANCE AND INVOLVE RISKS AND UNCERTAINTIES, AND THAT ACTUAL RESULTS MAY
DIFFER MATERIALLY FROM THOSE IN THE FORWARD-LOOKING STATEMENTS AS A RESULT OF
VARIOUS FACTORS INCLUDING, BUT NOT LIMITED TO: (I) GENERAL ECONOMIC CONDITIONS
IN THE MARKETS IN WHICH THE COMPANY OPERATES; (II) FLUCTUATIONS IN WORLDWIDE OR
REGIONAL AUTOMOBILE AND LIGHT AND HEAVY TRUCK PRODUCTION; (III) LABOR DISPUTES
INVOLVING THE COMPANY OR ITS SIGNIFICANT CUSTOMERS; (IV) CHANGES IN PRACTICES
AND/OR POLICIES OF THE COMPANY'S SIGNIFICANT CUSTOMERS TOWARD OUTSOURCING
AUTOMOTIVE COMPONENTS AND SYSTEMS; (V) FOREIGN CURRENCY AND EXCHANGE
FLUCTUATIONS; AND (VI) OTHER RISKS DETAILED FROM TIME TO TIME IN THE COMPANY'S
FILINGS WITH THE SECURITIES AND EXCHANGE COMMISSION. THE COMPANY DOES NOT INTEND
TO UPDATE THESE FORWARD-LOOKING STATEMENTS.



                                       7

<PAGE>   8


Material Changes in Financial Condition

Operating activities used $2.8 million in the six months ended June 30, 1998.
Accounts receivable increased $1.8 million from December 31, 1997, as sales
during June 1998 were higher than those of December 1997 due to the traditional
holiday shutdown. In addition, because June only has 30 days, customer payments
which would have been received on the 31st day of the month were received on the
first day of the third quarter. Depreciation and amortization expense was $1.3
million. Additions to property, plant and equipment were $0.9 million during the
six months ended June 30, 1998. The cash consumed in operating and investing
activities was fully funded by Intermet. The Company's financial condition has
deteriorated since the fourth quarter of 1995 and the Company remains dependent
on Intermet for continued financial support. Cumulative losses since 1988, when
the Company was acquired by Intermet, are approximately $77.3 million.

Material Changes in Results of Operations

Sales for the quarters ended June 30, 1998 and 1997 were $13.5 million and $13.4
million, respectively. Sales for the six months ended June 30, 1998 were $27.9
million, up from $25.9 million for the same period in 1997. This increase
relates to new business, primarily with Advance Castings and Dana and increases
in existing business. This new business has not fully replaced that of the Ford
F-150 I-beam, the phase-out of which began in the fourth quarter 1995 following
a model change. The Company launched new business for the dry sand process line
in June 1998 which is expected to provide additional volume for the Company. The
Company continues to evaluate alternatives to improve profitability as it is
currently operating below breakeven levels due to under-utilization of capacity
and less than optimal manufacturing performance.

Gross profit as a percentage of sales for the second quarter of 1998 was
negative 6.8% compared to a negative 4.2% for the second quarter of 1997. This
decrease was due primarily to a difference in the mix of product between the two
periods. Gross profit as a percentage of sales for the six months ended June 30,
1998 and 1997 were negative 4.8% and negative 7.3%. The improvement over last
year is due primarily to the increase in sales, cost reduction measures
implemented by the Company and a change in accounting policy, all in the first
quarter of 1998.

The Company's income tax provision is calculated and reported as if the Company
filed a separate federal income tax return. The Company has net operating loss
carryforwards available at June 30, 1998 which are fully reserved. As such, the
Company has no tax provision for the quarter ended or the six-month period ended
June 30, 1998.

As a result of the continued low sales volume, the Company incurred a loss of
$1.4 million in the second quarter of 1998 and $2.0 million for the calendar
year to date period June 30, 1998.


                         PART II - OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS

The Company is not aware of any material pending or threatened legal proceedings
to which the Company is a party or of which any of its property is the subject.



                                       8

<PAGE>   9
ITEM 2. CHANGES IN SECURITIES AND USE OF PROCEEDS

None

ITEM 3. DEFAULTS UPON SENIOR SECURITIES

None

ITEM 4. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

As of April 16, 1998, Intermet, sole owner of the Company's common stock,
elected by written consent the following individuals to serve on the Board of
Directors of the Company until the next annual meeting and until their
successors are elected and qualified: John Doddridge, C. James Peterson and
Doretha J. Christoph.

ITEM 5. OTHER INFORMATION

None

ITEM 6. EXHIBITS AND REPORTS ON FORM 8-K

(a) The following exhibits are filed with this Report pursuant to Item 601 of
Regulation S-K:



Exhibit Number   Description of Exhibit

27               Financial Data Schedule.

(b) The Company filed no reports on Form 8-K for the three months ended June 30,
1998.


                                   SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Company
has duly caused this report to be signed on its behalf by the undersigned
thereunto duly authorized.

                                    IRONTON IRON, INC.



                                    By:   /s/ Doretha J. Christoph
                                          ------------------------
                                          Doretha J. Christoph
                                          Vice President, Secretary, Treasurer
                                          and Director (Principal Financial
                                          and Accounting Officer)

                                    Date: August 13, 1998


 
                                      9

<PAGE>   10


Exhibits Index




Exhibit Number   Description of Exhibit

27               Financial Data Schedule.









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