-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 ewAx5pYJSU6lCmTkm6i47w==

<SEC-DOCUMENT>0001180872-04-000004.txt : 20040729
<SEC-HEADER>0001180872-04-000004.hdr.sgml : 20040729
<ACCEPTANCE-DATETIME>20040729095805
ACCESSION NUMBER:		0001180872-04-000004
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040728
FILED AS OF DATE:		20040729

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			COBLIN JAMES M
		CENTRAL INDEX KEY:			0001180872

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-04119
		FILM NUMBER:		04937602

	BUSINESS ADDRESS:	
		STREET 1:		2100 REXFORD RD
		CITY:			CHARLOTTE
		STATE:			NC
		ZIP:			28211
		BUSINESS PHONE:		7043667000

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NUCOR CORP
		CENTRAL INDEX KEY:			0000073309
		STANDARD INDUSTRIAL CLASSIFICATION:	STEEL WORKS, BLAST FURNACES  ROLLING MILLS (COKE OVENS) [3312]
		IRS NUMBER:				131860817
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2100 REXFORD RD
		CITY:			CHARLOTTE
		STATE:			NC
		ZIP:			28211
		BUSINESS PHONE:		7043667000

	MAIL ADDRESS:	
		STREET 1:		2100 REXFORD ROAD
		CITY:			CHARLOTTE
		STATE:			NC
		ZIP:			28211

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NUCLEAR CORP OF AMERICA INC
		DATE OF NAME CHANGE:	19680911

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	AZTEC MECHANICAL CONTRACTORS INC
		DATE OF NAME CHANGE:	19660629
</SEC-HEADER>
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<TYPE>4
<SEQUENCE>1
<FILENAME>c0001180872d20040729f4f.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
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<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-07-28</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000073309</issuerCik>
        <issuerName>NUCOR CORP</issuerName>
        <issuerTradingSymbol>NUE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001180872</rptOwnerCik>
            <rptOwnerName>COBLIN JAMES M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2100 REXFORD ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHARLOTTE</rptOwnerCity>
            <rptOwnerState>NC</rptOwnerState>
            <rptOwnerZipCode>28211-</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VICE PRESIDENT</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-07-28</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2004-07-28</value>
            </deemedExecutionDate>
            <transactionCoding>
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            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2477</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>44.4</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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                <transactionPricePerShare>
                    <value>47.1</value>
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                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
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                <sharesOwnedFollowingTransaction>
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            <transactionAmounts>
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                <transactionPricePerShare>
                    <value>81.9787</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
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            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8998</value>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
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            <securityTitle>
                <value>Common Stock</value>
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            <transactionDate>
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            </transactionDate>
            <deemedExecutionDate>
                <value>2004-07-28</value>
            </deemedExecutionDate>
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                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2084</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>82.07</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6914</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-07-28</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2004-07-28</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1060</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>81.9915</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5854</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>44.4</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-07-28</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2004-07-28</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
                <transactionShares>
                    <value>2477</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2001-09-01</value>
            </exerciseDate>
            <expirationDate>
                <value>2008-02-29</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2477</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
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        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>47.1</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-07-28</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2004-07-28</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
                <transactionShares>
                    <value>881</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
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                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2000-03-01</value>
            </exerciseDate>
            <expirationDate>
                <value>2006-08-31</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>881</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
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                    <value>0</value>
                </sharesOwnedFollowingTransaction>
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                <directOrIndirectOwnership>
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        <derivativeTransaction>
            <securityTitle>
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                <value>2004-07-28</value>
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            <expirationDate>
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    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>Kelly J. Wilmoth - Attorney-in-fact</signatureName>
        <signatureDate>2004-07-29</signatureDate>
    </ownerSignature>
</ownershipDocument>

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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----