<SEC-DOCUMENT>0001628280-18-003187.txt : 20180314
<SEC-HEADER>0001628280-18-003187.hdr.sgml : 20180314
<ACCEPTANCE-DATETIME>20180314164753
ACCESSION NUMBER:		0001628280-18-003187
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180312
FILED AS OF DATE:		20180314
DATE AS OF CHANGE:		20180314

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			DONNAN JOHN MALCOLM
		CENTRAL INDEX KEY:			0001311544

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09447
		FILM NUMBER:		18690011

	MAIL ADDRESS:	
		STREET 1:		C/O KAISER ALUMINUM CORP
		STREET 2:		27422 PORTOLA PARKWAY, SUITE 350
		CITY:			FOOTHILL RANCH
		STATE:			CA
		ZIP:			92610-2831

	FORMER NAME:	
		FORMER CONFORMED NAME:	Donnan John Malcolm
		DATE OF NAME CHANGE:	20041215

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			KAISER ALUMINUM CORP
		CENTRAL INDEX KEY:			0000811596
		STANDARD INDUSTRIAL CLASSIFICATION:	ROLLING DRAWING & EXTRUDING OF NONFERROUS METALS [3350]
		IRS NUMBER:				943030279
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		27422 PORTOLA PARKWAY, SUITE 200
		CITY:			FOOTHILL RANCH
		STATE:			CA
		ZIP:			92610-2831
		BUSINESS PHONE:		949-614-1740

	MAIL ADDRESS:	
		STREET 1:		27422 PORTOLA PARKWAY, SUITE 200
		CITY:			FOOTHILL RANCH
		STATE:			CA
		ZIP:			92610-2831

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	KAISERTECH LTD
		DATE OF NAME CHANGE:	19901122
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_152106046012110.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-03-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000811596</issuerCik>
        <issuerName>KAISER ALUMINUM CORP</issuerName>
        <issuerTradingSymbol>KALU</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001311544</rptOwnerCik>
            <rptOwnerName>DONNAN JOHN MALCOLM</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O KAISER ALUMINUM CORP.</rptOwnerStreet1>
            <rptOwnerStreet2>27422 PORTOLA PARKWAY SUITE 200</rptOwnerStreet2>
            <rptOwnerCity>FOOTHILL RANCH</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92610</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP - Legal, Compliance &amp; HR</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2018-03-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>6783</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>107.1032</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>19078</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents the sale of 6,783 shares in multiple transactions, ranging from $106.69 to $107.60 per share, resulting in a weighted average sale price of $107.1032 per share. The reporting person undertakes to provide upon request by the SEC staff, the Registrant, or a security holder of the Registrant, full information regarding the number of shares sold at each separate price within the range.</footnote>
        <footnote id="F2">Includes 11,237 shares acquired pursuant to grants of restricted stock units.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Cherrie I. Tsai, with power of attorney for John M. Donnan</signatureName>
        <signatureDate>2018-03-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
