<SEC-DOCUMENT>0001628280-21-011753.txt : 20210607
<SEC-HEADER>0001628280-21-011753.hdr.sgml : 20210607
<ACCEPTANCE-DATETIME>20210607171155
ACCESSION NUMBER:		0001628280-21-011753
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210603
FILED AS OF DATE:		20210607
DATE AS OF CHANGE:		20210607

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MARTIN LAURALEE
		CENTRAL INDEX KEY:			0001164495

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09447
		FILM NUMBER:		211000339

	MAIL ADDRESS:	
		STREET 1:		JONES LANG LASALLE INCORPORATED
		STREET 2:		200 E RANDOLPH DR
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60601

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_162310030241428.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-06-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001164495</rptOwnerCik>
            <rptOwnerName>MARTIN LAURALEE</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>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2021-06-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>952</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10845</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2021-06-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>609</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>131.21</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11454</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Grant to the reporting person of restricted stock under the Kaiser Aluminum Corporation 2021 Equity and Incentive Compensation Plan. All restrictions will lapse on June 3, 2022.</footnote>
        <footnote id="F2">Stock received by the reporting person under the Kaiser Aluminum Corporation 2021 Equity and Incentive Compensation Plan at such person's election in lieu of all or a portion of the reporting person's annual cash retainer for serving as a member of the Board of Directors of Kaiser Aluminum Corporation or chair of a committee of the Board of Directors.</footnote>
        <footnote id="F3">Equal to the average of the closing prices of the Issuer's common stock as reported by the Nasdaq Stock Market, LLC for the twenty trading days prior to June 3, 2021.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Cherrie I. Tsai, with power of attorney for Lauralee E. Martin</signatureName>
        <signatureDate>2021-06-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
