<SEC-DOCUMENT>0001628280-20-009380.txt : 20200612
<SEC-HEADER>0001628280-20-009380.hdr.sgml : 20200612
<ACCEPTANCE-DATETIME>20200612185854
ACCESSION NUMBER:		0001628280-20-009380
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20200610
FILED AS OF DATE:		20200612
DATE AS OF CHANGE:		20200612

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Wilcox Brett
		CENTRAL INDEX KEY:			0001289226

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09447
		FILM NUMBER:		20961609

	MAIL ADDRESS:	
		STREET 1:		1000 SW BROADWAY, SUITE 2200
		CITY:			PORTLAND
		STATE:			OR
		ZIP:			97205

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_159200271516907.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-06-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001289226</rptOwnerCik>
            <rptOwnerName>Wilcox Brett</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>2020-06-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1756</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2941</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>2020-06-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>491</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>71.15</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3432</value>
                </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>11612</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Wilcox Revocable Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Grant to the reporting person of restricted stock under the Kaiser Aluminum Corporation 2016 Equity and Incentive Compensation Plan. All restrictions will lapse on June 10, 2021.</footnote>
        <footnote id="F2">Stock received by the reporting person under the Kaiser Aluminum Corporation 2016 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.</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 10, 2020.</footnote>
        <footnote id="F4">Reflects shares previously held directly by the reporting person that were transferred into the Wilcox Revocable Trust in a transaction exempt from Section 16 reporting pursuant to Rule 16a-13.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Cherrie I. Tsai, with power of attorney for Brett E. Wilcox</signatureName>
        <signatureDate>2020-06-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
