<SEC-DOCUMENT>0000098362-19-000108.txt : 20190920
<SEC-HEADER>0000098362-19-000108.hdr.sgml : 20190920
<ACCEPTANCE-DATETIME>20190920150831
ACCESSION NUMBER:		0000098362-19-000108
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20190820
FILED AS OF DATE:		20190920
DATE AS OF CHANGE:		20190920

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Chadwick Shelly Marie
		CENTRAL INDEX KEY:			0001688289

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-01169
		FILM NUMBER:		191104369

	MAIL ADDRESS:	
		STREET 1:		4500 MOUNT PLEASANT ST NW
		CITY:			NORTH CANTON
		STATE:			OH
		ZIP:			44720

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TIMKEN CO
		CENTRAL INDEX KEY:			0000098362
		STANDARD INDUSTRIAL CLASSIFICATION:	BALL & ROLLER BEARINGS [3562]
		IRS NUMBER:				340577130
		STATE OF INCORPORATION:			OH
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		4500 MT. PLEASANT ST. NW
		CITY:			NORTH CANTON
		STATE:			OH
		ZIP:			44720-5450
		BUSINESS PHONE:		(234) 262-3000

	MAIL ADDRESS:	
		STREET 1:		4500 MT. PLEASANT ST. NW
		CITY:			NORTH CANTON
		STATE:			OH
		ZIP:			44720-5450

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	TIMKEN ROLLER BEARING CO
		DATE OF NAME CHANGE:	19710304
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_156900649552511.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-08-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000098362</issuerCik>
        <issuerName>TIMKEN CO</issuerName>
        <issuerTradingSymbol>TKR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001688289</rptOwnerCik>
            <rptOwnerName>Chadwick Shelly Marie</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>4500 MT. PLEASANT ST. NW</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NORTH CANTON</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>44720</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Accounting Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2019-08-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>I</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1183</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>40</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>401 (k)</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">On June 26, 2018, the Company announced that effective January 1, 2019 the primary U.S. Company sponsored 401(k) plan would no longer allow contributions to be made to the employer stock fund to align with industry trends to remove investment in the employer's stock as an option in a company sponsored 401(k) plan. All participants in this plan, including the named officer, are required to transfer remaining funds in the employer stock fund to other fund options by December 31, 2022.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Shelly M. Chadwick</signatureName>
        <signatureDate>2019-09-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
