<SEC-DOCUMENT>0001628280-22-005435.txt : 20220308
<SEC-HEADER>0001628280-22-005435.hdr.sgml : 20220308
<ACCEPTANCE-DATETIME>20220308174442
ACCESSION NUMBER:		0001628280-22-005435
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20220305
FILED AS OF DATE:		20220308
DATE AS OF CHANGE:		20220308

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ELLSWORTH MELINDA C
		CENTRAL INDEX KEY:			0001194571

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09447
		FILM NUMBER:		22722974

	MAIL ADDRESS:	
		STREET 1:		408 EAST SECOND STREET
		STREET 2:		PO BOX 1109
		CITY:			MUSCATINE
		STATE:			IA
		ZIP:			52761

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_164677945863786.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2022-03-05</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001194571</rptOwnerCik>
            <rptOwnerName>ELLSWORTH MELINDA C</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>VP IR &amp; Corp. Communications</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2022-03-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>996</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3581</value>
                    <footnoteId id="F2"/>
                </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>2022-03-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>304</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3885</value>
                    <footnoteId id="F2"/>
                </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>2022-03-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F4"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>125</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>95.13</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3760</value>
                    <footnoteId id="F2"/>
                </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>2022-03-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F5"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>328</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>95.13</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3432</value>
                    <footnoteId id="F6"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6852</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Ellsworth Revocable Living Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Grant to the reporting person effective as of March 5, 2022 of restricted stock units under the Kaiser Aluminum Corporation 2021 Equity and Incentive Compensation Plan. All restrictions will lapse on March 5, 2025 or earlier upon the occurrence of certain specified circumstances.</footnote>
        <footnote id="F2">Includes 3,581 shares acquired pursuant to grants of restricted stock units.</footnote>
        <footnote id="F3">Shares earned upon the vesting on March 5, 2022 of certain performance shares granted to the reporting person in 2019 under the Kaiser Aluminum Corporation 2016 Equity and Incentive Compensation Plan. On March 5, 2022, the Registrant's compensation committee certified the performance shares payout multiplier based on the level of achievement by the Registrant of certain pre-established performance goals for 2019 through 2021.</footnote>
        <footnote id="F4">Shares withheld to satisfy the withholding tax obligations resulting from the vesting on March 5, 2022 of the above-referenced performance shares.</footnote>
        <footnote id="F5">Shares withheld to satisfy the withholding tax obligations resulting from the vesting on March 5, 2022 of certain restricted stock units granted to the reporting person in 2019 under the Kaiser Aluminum Corporation 2016 Equity and Incentive Compensation Plan.</footnote>
        <footnote id="F6">Includes 2,758 shares acquired pursuant to grants of restricted stock units.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Cherrie I. Tsai, with power of attorney for Melinda C. Ellsworth</signatureName>
        <signatureDate>2022-03-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
