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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 E6OHCzXK7YEU5af4obMB7HHicMLOej4sfRN6bbrA3D/ViM47TJu8qPCygrz4u1hF
 7d5mqSGAbuiIhxozu9QKvQ==

<SEC-DOCUMENT>0001448973-10-000001.txt : 20100816
<SEC-HEADER>0001448973-10-000001.hdr.sgml : 20100816
<ACCEPTANCE-DATETIME>20100816170529
ACCESSION NUMBER:		0001448973-10-000001
CONFORMED SUBMISSION TYPE:	5
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100630
FILED AS OF DATE:		20100816
DATE AS OF CHANGE:		20100816

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ARMSTRONG TIMOTHY
		CENTRAL INDEX KEY:			0001448973

	FILING VALUES:
		FORM TYPE:		5
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05828
		FILM NUMBER:		101020796

	MAIL ADDRESS:	
		STREET 1:		C/O CARPENTER TECHNOLOGY CORPORATION
		STREET 2:		PO BOX 14662
		CITY:			READING
		STATE:			PA
		ZIP:			19612

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CARPENTER TECHNOLOGY CORP
		CENTRAL INDEX KEY:			0000017843
		STANDARD INDUSTRIAL CLASSIFICATION:	STEEL WORKS, BLAST FURNACES  ROLLING MILLS (COKE OVENS) [3312]
		IRS NUMBER:				230458500
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		2 MERIDIAN BOULEVARD
		CITY:			WYOMISSING
		STATE:			PA
		ZIP:			19612
		BUSINESS PHONE:		6102082000

	MAIL ADDRESS:	
		STREET 1:		PO BOX 14662
		CITY:			READING
		STATE:			PA
		ZIP:			19612-4662
</SEC-HEADER>
<DOCUMENT>
<TYPE>5
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2010-06-30</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0000017843</issuerCik>
        <issuerName>CARPENTER TECHNOLOGY CORP</issuerName>
        <issuerTradingSymbol>CRS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001448973</rptOwnerCik>
            <rptOwnerName>ARMSTRONG TIMOTHY</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>CARPENTER TECHNOLOGY CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>PO BOX 14662</rptOwnerStreet2>
            <rptOwnerCity>READING</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19612</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President - R&amp;D</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10509</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>K. Douglas Ralph/POA</signatureName>
        <signatureDate>2010-08-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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