<PAGE>

                                                                  EXHIBIT 4.2(a)
 
     THIS NOTE (OR ITS PREDECESSOR) HAS NOT BEEN REGISTERED UNDER THE UNITED
     STATES SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND,
     ACCORDINGLY, MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED
     WITHIN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR BENEFIT OF, U.S.
     PERSONS, EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE.  BY ITS ACQUISITION
     HEREOF OR OF A BENEFICIAL INTEREST HEREIN, THE HOLDER:
 
     (1) REPRESENTS THAT (A) IT IS A "QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED
     IN RULE 144A UNDER THE SECURITIES ACT)(A "QIB"), OR (B) IT HAS ACQUIRED
     THIS NOTE IN AN OFFSHORE TRANSACTION IN COMPLIANCE WITH REGULATION S
     UNDER THE SECURITIES ACT,

     (2) AGREES THAT IT WILL NOT, RESELL OR OTHERWISE TRANSFER THIS NOTE EXCEPT
     (A) TO THE COMPANY OR ANY OF ITS SUBSIDIARIES, (B) TO A PERSON WHOM THE
     SELLER REASONABLY BELIEVES IS A QIB PURCHASING FOR ITS OWN ACCOUNT OR FOR
     THE ACCOUNT OF A QIB IN A TRANSACTION MEETING THE REQUIREMENTS OF RULE
     144A, (C) IN AN OFFSHORE TRANSACTION MEETING THE REQUIREMENTS OF RULE 903
     OR 904 OF THE SECURITIES ACT, (D) IN A TRANSACTION MEETING THE REQUIREMENTS
     OF RULE 144 UNDER THE SECURITIES ACT, (E) IN ACCORDANCE WITH ANOTHER
     EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT (AND
     BASED UPON AN OPINION OF COUNSEL ACCEPTABLE TO THE COMPANY) OR (F) PURSUANT
     TO AN EFFECTIVE REGISTRATION STATEMENT AND, IN EACH CASE, IN ACCORDANCE
     WITH THE APPLICABLE SECURITIES LAWS OF ANY STATE OF THE UNITED STATES OR
     ANY OTHER APPLICABLE JURISDICTION AND

     (3) AGREES THAT IT WILL DELIVER TO EACH PERSON TO WHOM THIS NOTE OR AN
     INTEREST HEREIN IS TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS
     LEGEND.
<PAGE>
 
     AS USED HEREIN, THE TERMS "OFFSHORE TRANSACTION" AND "UNITED STATES" HAVE
     THE MEANINGS GIVEN TO THEM BY RULE 902 OF REGULATION S UNDER THE SECURITIES
     ACT. THE INDENTURE CONTAINS A PROVISION REQUIR ING THE TRUSTEE TO REFUSE TO
     REGISTER ANY TRANSFER OF THIS NOTE IN VIOLATION OF THE FOREGOING.

     UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
     DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE COMPANY OR
     ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY
     CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER
     NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY
     PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN
     AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF
     FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE
     REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

     TRANSFERS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS IN WHOLE,
     BUT NOT IN PART, TO NOMINEES OF CEDE & CO. OR TO A SUCCESSOR THEREOF OR
     SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL SECURITY
     SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET
     FORTH IN SECTIONS 311 AND 312 OF THE INDENTURE DATED AS OF MARCH 24, 1998
     BETWEEN THE COMPANY AND UNITED STATES TRUST COMPANY OF NEW YORK AS TRUSTEE.
<PAGE>
 
                          EARLE M. JORGENSEN COMPANY

                         9 1/2% Senior Notes due 2005

No.  N-001                                                          $100,000,000

                                                              CUSIP No.480829AB6

          Earle M. Jorgensen Company, a Delaware corporation (herein called the
"Company", which term includes any successor Person under the Indenture
hereinafter referred to), for value received, hereby promises to pay to CEDE &
CO., or its registered assigns, the principal sum of One Hundred Million
($100,000,000) Dollars on April 1, 2005 at the office or agency of the Company
referred to below, and to pay interest thereon on October 1, 1998 and semi-
annually thereafter, on April 1 and October 1 in each year, from October 1,
1998, or from the most recent Interest Payment Date to which interest has been
paid or duly provided for, at the rate of 9 1/2% per annum, until the principal
hereof is paid or duly provided for, and (to the extent lawful) to pay on demand
interest on any overdue interest at the rate borne by the Notes from the date on
which such overdue interest becomes payable to the date on which payment of such
interest has been made or duly provided for.  The interest so payable, and
punctually paid or duly provided for, on any Interest Payment Date will, as
provided in such Indenture, be paid to the Person in whose name this Note (or
one or more Predecessor Notes) is registered at the close of business on the
Record Date for such interest, which shall be the March 15 or September 15
(whether or not a Business Day), as the case may be, next preceding such
Interest Payment Date.  Any such interest not so punctually paid or duly
provided for shall forthwith cease to be payable to the Holder on such Record
Date, and such defaulted interest, and (to the extent lawful) interest on such
defaulted interest at the rate borne by the Notes, may be paid to the Person in
whose name this Note (or one or more Predecessor Notes) is registered at the
close of business on a Special Record Date for the payment of such Defaulted
Interest to be fixed by the Trustee, notice whereof shall be given to Holders of
Notes not less than 10 days prior to such Special Record Date, or may be paid at
any time in any other lawful manner not inconsistent with the requirements of
any securities exchange on which the Notes may be listed, and upon such notice
as may be required by such exchange, all as more fully provided in said
Indenture.  Payment of the principal of (and premium, if any, on) and interest
on this Note will be made at the office or agency of the Company maintained for
that purpose in The City of New York, or at such other office or agency of the
Company as may be maintained for such purpose, in such coin or currency of the
United States 
<PAGE>
 
of America as at the time of payment is legal tender for payment of public and
private debts; provided, however, that payment of interest may be made at the
               --------  -------                                 
option of the Company (i) by check mailed to the address of the Person entitled
thereto as such address shall appear on the Note Register or (ii) by transfer to
an account maintained by the payee located in the United States.

          Reference is hereby made to the further provisions of this Note set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

          Unless the certificate of authentication hereon has been duly executed
by the Trustee referred to on the reverse hereof by manual signature, this Note
shall not be entitled to any benefit under the Indenture, or be valid or
obligatory for any purpose.
<PAGE>
 
          IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed.

     Dated: March 24, 1998          EARLE M. JORGENSEN COMPANY


                                    By /s/ Charles P. Gallopo
                                      --------------------------------
                                      Title:  Vice President and Chief
                                              Financial Officer
Attest:

/s/ William S. Johnson
----------------------
Authorized Signature

                   TRUSTEE'S CERTIFICATE OF AUTHENTICATION.

                   Dated:  March 24, 1998
                           --------------

                   This is one of the Notes referred to in the within-mentioned
Indenture.

                              UNITED STATES TRUST 
                              COMPANY
                              OF NEW YORK

                              /s/ Gerard F. Ganey,  as Trustee
                              --------------------             
                              By: Gerard F. Ganey
                                  Authorized Officer
<PAGE>
 
                               [Reverse of Note]

          This Note is one of a duly authorized issue of securities of the
Company designated as its 9 1/2% Senior Notes due 2005 (herein called the
"Notes"), limited (except as otherwise provided in the Indenture referred to
below) in aggregate principal of $105,000,000, that may be issued under a Senior
Notes Indenture (herein called the "Indenture") dated as of March 24, 1998
between the Company and United States Trust Company of New York (herein called
the "Trustee", which term includes any successor trustee under the Indenture),
to which Indenture and all indentures supplemental thereto reference is hereby
made for a statement of the respective rights, limitations of rights, duties,
obligations and immunities thereunder of the Company, the Trustee and the
Holders of the Notes, and of the terms upon which the Notes are, and are to be,
authenticated and delivered.

          The Company, at its option, may redeem the Notes as a whole, or from
time to time in part, on or after April 1, 2002, at the redemption prices 
(expressed as a percentage of the principal amount thereof) set forth below (in
each case together with accrued and unpaid interest, if any, to the Redemption
Date):

<TABLE>
<CAPTION>
 IF REDEEMED DURING THE 12-MONTH
    PERIOD BEGINNING APRIL 1,        REDEMPTION PRICE
<S>                                  <C>
      2002........................            104.750%
      2003........................            102.375%
      2004 and thereafter.........            100.000%
</TABLE>

     Notwithstanding the foregoing, prior to April 1, 2001, the Company may
redeem from time to time up to 35% of the aggregate principal amount of the
Notes originally outstanding at a redemption price equal to 109.5% of the
principal amount thereof, plus accrued and unpaid interest, if any to the
redemption date, with the net proceeds of a public offering of common stock by
the Company (or of Holding to the extent such net proceeds are contributed as a
capital contribution in exchange for common stock of the Company); provided that
at least 65% of the aggregate principal amount of the Notes originally
outstanding remain outstanding immediately after such redemption.

          Upon the occurrence of a Change of Control (the "Change of Control
Date"), each Holder shall have the right, at such Holder's option, to require
the Company to repurchase all or any part of such Holder's Notes pursuant to the
offer (the "Change of Control Offer") at a purchase price equal to 101% of the
principal 
<PAGE>
 
amount thereof (the "Change of Control Purchase Price"), plus accrued and unpaid
interest, if any, to the date of repurchase.

          The Holder of this Note is entitled to the benefits of the
Registration Rights Agreement, dated March 24, 1998, among the Company and the
Initial Purchasers named therein (the "Registration Rights Agreement"). The
Registration Rights Agreement will provide that (i) if the Company fails to file
an Exchange Offer Registration Statement with the Commission on or prior to the
90th day after the Closing Date, (ii) if the Exchange Offer Registration
Statement is not declared effective by the Commission on or prior to the 150th
day after the Closing Date, (iii) if the Exchange Offer is not consummated on or
before the 30th calendar day after the Exchange Offer Registration Statement is
declared effective, (iv) if obligated to file the Shelf Registration Statement
and the Company fails to file the Shelf Registration Statement with the
Commission on or prior to the 90th day after such filing obligation arises, (v)
if obligated to file a Shelf Registration Statement and the Shelf Registration
Statement is not declared effective on or prior to the 150th day after the
obligation to file a Shelf Registration Statement arises, or (vi) if the
Exchange Offer Registration Statement or the Shelf Registration Statement, as
the case may be, is declared effective but thereafter ceases to be effective or
useable in connection with resales of the Transfer Restricted Securities,
without being succeeded immediately by a post-effective amendment to such
Registration Statement that cures such failure and that is itself declared
effective immediately (each, a "Registration Default"), the Company agrees to
pay to each Holder of Transfer Restricted Securities affected thereby liquidated
damages "(Liquidated Damages") in an amount equal to $0.05 per week per $1,000
in principal amount of Transfer Restricted Securities held by such Holder for
each week or portion thereof that the Registration Default continues for the
first 90 day period immediately following the occurrence of such Registration
Default. The amount of the Liquidated Damages shall increase by an additional
$0.05 per week per $1,000 in principal amount of Transfer Restricted Securities
with respect to each subsequent 90 day period until all Registration Defaults
have been cured, up to a maximum amount of Liquidated Damages of $0.50 per week
$1,000 principal amount of Transfer Restricted Securities. The Company shall not
be required to pay Liquidated Damages for more than one Registration Default at
any given time. Following the cure of all Registration Defaults, the accrual of
Liquidated Damages will cease.


          In the case of any redemption of Notes, interest installments whose
Stated Maturity is on or prior to the Redemption Date will be payable to the
Holders 
<PAGE>
 
of such Notes, or one or more Predecessor Notes, of record at the close
of business on the relevant Regular Record Date referred to on the face hereof.
Notes (or portions thereof) for whose redemption and payment provision is made
in accordance with the Indenture shall cease to bear interest from and after the
Redemption Date.

          All accrued Liquidated Damages shall be paid by the Company to Holders
entitled thereto by wire transfer to the accounts specified by them or by
mailing checks to their registered address if no such accounts have been
specified.

          In the event of redemption of this Note in part only, a new Note or
Notes for the unredeemed portion hereof shall be issued in the name of the
Holder hereof upon the cancellation hereof.

          The Indenture defines an Event of Default as being: (a) any failure to
pay an installment of interest on the Notes as and when the same becomes due and
payable and such failure continues for 30 days; (b) failure to pay all or any
part of the principal of (or premium, if any, on) the Notes when and as the same
shall become due and payable at maturity, redemption, by declaration or
otherwise, including payment of the Change of Control Purchase Price; (c)
failure by the Company duly to observe, perform or comply with any covenant or
agreement contained in the Notes or the Indenture which failure continues for a
period of 60 days after written notice specifying such failure and demanding
that the Company remedy the same has been given to the Company by the Trustee or
to the Company and the Trustee by Holders of at least 25% in aggregate principal
amount of Notes then outstanding; (d) certain events of bankruptcy, insolvency
or reorganization in respect of the Company or any Material Subsidiary; (e) (i)
a default which extends beyond any stated period of grace applicable thereto,
excluding any extension thereof, under any bond, debenture, note, mortgage,
indenture or instrument under which there may be issued or by which there may be
secured or evidenced any Indebtedness of the Company or any of its Restricted
Subsidiaries, whether now existing or hereafter created, aggregating in excess
of $10,000,000 at any one time, if as a result of such event of default the
maturity of such Indebtedness has been accelerated prior to its final stated
maturity, or (ii) failure to pay such Indebtedness, aggregating in principal
amount in excess of $10,000,000 at any one time, at its final stated maturity;
or (f) the rendering of final judgments not covered by insurance (which coverage
shall be in full force and effect) for the payment of money in an amount equal
to or greater than, in the case of any one such judgment $2,500,000, and, in the
case of all such judgments $5,000,000, against the Company or any of its
Restricted Subsidiaries by a court of
<PAGE>
 
competent jurisdiction which are not stayed, satisfied or discharged within 60
days after such judgments become final and nonappealable.

          If an Event of Default (other than an Event of Default with respect to
the Company described in clause (d) of the preceding paragraph), shall occur and
be continuing then, and in every such case, unless the principal of all the
Notes shall have already become due and payable, either the Trustee or the
Holders of not less than 25% in aggregate principal amount of then outstanding
Notes, by notice in writing to the Company (and to the Trustee if given by
Holders), may declare all of the principal of the Notes (or the Change of
Control Purchase Price if the Event of Default includes failure to pay the
Change of Control Purchase Price), together with accrued interest thereon to be
due and payable immediately. If an Event of Default with respect to the Company
specified in clause (d) above occurs, all principal of, premium applicable to,
and accrued interest on, all then outstanding Notes shall become immediately due
and payable without any declaration or other act on the part of the Trustee or
any Holder.

          The Indenture contains provisions for defeasance at any time of (a)
the entire indebtedness of the Company on this Note and (b) certain restrictive
covenants and the related Defaults and Events of Default, upon compliance by the
Company with certain conditions set forth therein, which provisions apply to
this Note.

          The Indenture permits, with certain exceptions as therein provided,
the amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders under the Indenture at any time by the
Company and the Trustee with the consent of the Holders of a majority in
aggregate principal amount of the Notes at the time Outstanding.  The Indenture
also contains provisions permitting the Holders of specified percentages in
aggregate principal amount of the Notes at the time Outstanding, on behalf of
the Holders of all the Notes, to waive compliance by the Company with certain
provisions of the Indenture and certain past defaults under the Indenture and
their consequences.  Any such consent or waiver by or on behalf of the Holder of
this Note shall be conclusive and binding upon such Holder and upon all future
Holders of this Note and of any Note issued upon the registration of transfer
hereof or in exchange therefor or in lieu hereof whether or not notation of such
consent or waiver is made upon this Note.

          No reference herein to the Indenture and no provision of this Note or
of the Indenture shall alter or impair the obligation of the Company, which is
<PAGE>
 
absolute and unconditional, to pay the principal of (and premium, if any) and
interest on this Note at the times, place, and rate, and in the coin or
currency, herein prescribed.

          As provided in the Indenture and subject to certain limitations
therein set forth, the transfer of this Note is registrable on the Note Register
of the Company, upon surrender of this Note for registration of transfer at the
office or agency of the Company maintained for such purpose in The City of New
York, duly endorsed by, or accompanied by a written instrument of transfer in
form satisfactory to the Company and the Note Registrar duly executed by, the
Holder hereof or his attorney duly authorized in writing, and thereupon one or
more new Notes, of authorized denominations and for the same aggregate principal
amount will be issued to the designated transferee or transferees.

          The Notes are issuable only in registered form without coupons in
denominations of $1,000 and any integral multiple thereof.  As provided in the
Indenture and subject to certain limitations therein set forth, the Notes are
exchangeable for a like aggregate principal amount of Notes of a different
authorized denomination, as requested by the Holder surrendering the same.

          No service charge shall be made for any registration of transfer or
exchange of Notes, but the Company may require payment of a sum sufficient to
cover any tax or other governmental charge payable in connection therewith.

          Prior to the time of due presentment of this Note for registration of
transfer, the Company, the Trustee and any agent of the Company or the Trustee
may treat the Person in whose name this Note is registered as the owner hereof
for all purposes, whether or not this Note be overdue, and neither the Company,
the Trustee nor any agent shall be affected by notice to the contrary.

          All terms used in this Note that are defined in the Indenture shall
have the meanings assigned to them in the Indenture.

          No recourse for the payment of the principal of, or premium, if any,
or interest on, any of the Notes or for any claim based thereon or otherwise in
respect thereof, and no recourse under or upon any obligation, covenant or
agreement of the Company in the Indenture or in any of the Notes, or because of
the creation of any Indebtedness represented thereby, shall be had against any
incorporator, stockholder, officer, director, employee, controlling person of
the Company or of a Subsidiary of the Company or of any successor Person of the
Company or of a Subsidiary of 
<PAGE>
 
the Company. Each Holder by accepting a Note waives and releases all such
liability, and such waiver and release is part of the consideration for the
issuance of the Notes.

          The Indenture and this Note shall be governed by, and construed in
accordance with, the internal laws of the State of New York (without giving
effect to the conflict of laws principles thereof).  The Trustee, the Company,
and (by their acceptance of the Notes) the Holders agree to submit to the non-
exclusive jurisdiction of any United States federal or state court located in
the Borough of Manhattan, in the City of New York, in any action or proceeding
arising out of or relating to the Indenture of this Note.

          Customary abbreviations may be used in the name of a Holder or an
assignee, such as:  TEN COM (= tenants in common), TEN ENT (= tenants by the
entireties), JT TEN (= joint tenants with right of survivorship and not as
tenants in common), CUST (= Custodian) and U/G/M/A (= Uniform Gifts to Minors
Act).

          The Company will furnish to any Holder upon written request and
without charge a copy of the Indenture.  Requests may be made to Earle M.
Jorgensen Company, 3050 East Birch Street, Brea, CA 92621, Attention: Chief
Financial Officer.
<PAGE>
 
                    [Form of Transfer Notice for the Notes]

          FOR VALUE RECEIVED the undersigned registered holder hereby sell(s),
assign(s) and transfer(s) unto

Insert Taxpayer Identification No.
----------------------------------


--------------------------------------------------------------------------------
(Please print or typewrite name and address including zip code of assignee)


--------------------------------------------------------------------------------
the within Note and all rights thereunder, hereby irrevocably constituting and
appointing


--------------------------------------------------------------------------------
attorney to transfer such Note on the books of the Company with full power of
substitution in the premises.
<PAGE>
 
          In connection with any transfer of this Note occurring prior to the
date which is the earlier of the date of an effective Registration Statement or
March 24, 2000; i.e., the end of the period referred to in Rule 144(k) under the
Securities Act, the undersigned confirms that without utilizing any general
solicitation or general advertising that:

                                   Check One
                                   ---------

   [_]    this Note is being transferred in compliance with the exemption from
          registration under the Securities Act of 1933, as amended, provided by
          Rule 144A thereunder.

                                      or
                                      --

   [_]    this Note is being transferred other than in accordance with (a) above
          and documents are being furnished which comply with the conditions of
          transfer set forth in this Note and the Indenture.

If none of the foregoing boxes is checked, the Trustee or other Note Registrar
shall not be obligated to register this Note in the name of any Person other
than the Holder hereof unless and until the conditions to any such transfer of
registration set forth herein and in Sections 311 and 312 of the Indenture shall
have been satisfied.


Date: __________________
 
                                     NOTICE: The signature to this assignment
                                     must correspond with the name as written
                                     upon the face of the within-mentioned
                                     instrument in every particular, without
                                     alteration or any change whatsoever.


Signature Guarantee:_______________________________________
<PAGE>
 
TO BE COMPLETED BY PURCHASER IF (a) ABOVE IS CHECKED.

          Signatures must be guaranteed by an "eligible guarantor institution"
meeting the requirements of the Note Registrar, which requirements include 
membership or participation in the Security Transfer Agent Medallion Program
("STAMP") or such other "signature guarantee program" as may be determined by
the Note Registrar in addition to, or in substitution for, STAMP, all in
accordance with the Securities Exchange Act of 1934, as amended.

          The undersigned represents and warrants that it is purchasing this
Note for its own account or an account with respect to which it exercises sole
investment discretion and that it and any such account is a "qualified
institutional buyer" within the meaning of Rule 144A under the Securities Act of
1933, as amended, and is aware that the sale to it is being made in reliance on
Rule 144A and acknowledges that it has received such information regarding the
Company as the undersigned has requested pursuant to Rule 144A or has determined
not to request such information and that it is aware that the transferor is
relying upon the under  signed's foregoing representations in order to claim the
exemption from registration provided by Rule 144A.


Dated:_____________________                  -----------------------------
                                             NOTICE:  To be executed by an
                                                      executive officer
<PAGE>
 
                      OPTION OF HOLDER TO ELECT PURCHASE


          If you wish to have this Note purchased by the Company pursuant to
Section 1201 or Section 1013 of the Indenture, check the Box: [_]

          If you wish to have a portion of this Note purchased by the Company
pursuant to Section 1201 or Section 1013 of the Indenture, state the amount (in
original principal amount) below:


                                $_____________________.


Date:  ______________________

Your Signature:  __________________________________

(Sign exactly as your name appears on the other side of this Note)

Signature Guarantee:  _____________________________________


          Signatures must be guaranteed by an "eligible guarantor institution"
meeting the requirements of the Note Registrar, which requirements include mem
bership or participation in the Security Transfer Agent Medallion Program
("STAMP") or such other "signature guarantee program" as may be determined by
the Note Registrar in addition to, or in substitution for, STAMP, all in
accordance with the Securities Exchange Act of 1934, as amended.