<SUBMISSION>
<ACCESSION-NUMBER>0001790982-20-000074
<TYPE>4/A
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20200403
<FILING-DATE>20200410
<DATE-OF-FILING-DATE-CHANGE>20200410
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>ONEAL E STANLEY
<CIK>0001182337
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4/A
<ACT>34
<FILE-NUMBER>001-39162
<FILM-NUMBER>20787603
</FILING-VALUES>
<MAIL-ADDRESS>
<STREET1>MERRILL LYNCH CORPORATE SECRETARY
<STREET2>222 BROADWAY, 17TH FLOOR
<CITY>NEW YORK
<STATE>NY
<ZIP>10038
</MAIL-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>Arconic Corp
<CIK>0001790982
<ASSIGNED-SIC>3350
<IRS-NUMBER>842745636
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>201 ISABELLA STREET
<CITY>PITTSBURGH
<STATE>PA
<ZIP>15212-5872
<PHONE>(412) 992-2500
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>201 ISABELLA STREET
<CITY>PITTSBURGH
<STATE>PA
<ZIP>15212-5872
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>Arconic Rolled Products Corp
<DATE-CHANGED>20191011
</FORMER-COMPANY>
</ISSUER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2020-04-03</periodOfReport>

    <dateOfOriginalSubmission>2020-04-07</dateOfOriginalSubmission>

    <issuer>
        <issuerCik>0001790982</issuerCik>
        <issuerName>Arconic Corp</issuerName>
        <issuerTradingSymbol>ARNC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001182337</rptOwnerCik>
            <rptOwnerName>ONEAL E STANLEY</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>201 ISABELLA STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 200</rptOwnerStreet2>
            <rptOwnerCity>PITTSBURGH</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>15212</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</value>
            </securityTitle>
            <transactionDate>
                <value>2020-04-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4776</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>95587</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents vested restricted stock units granted pursuant to the Arconic Corporation 2020 Stock Incentive Plan in respect of the reporting person's deferral of Howmet Aerospace Inc.'s (former Parent Company) director fees.  The deferred fee amount of $38,500 was converted into deferred restricted stock units based on the closing price of Arconic Corporation common stock on April 3, 2020.</footnote>
        <footnote id="F2">On April 1, 2020, Arconic Inc. completed the separation of its business into two independent, publicly-traded companies (the Separation): Howmet Aerospace Inc. and Arconic Corporation.  This Form 4 is being amended to reflect the total number of Arconic Corporation shares underlying equity awards held by the reporting person after reflecting the adjustment of all Arconic Inc. equity awards held by the reporting person as of the Separation to relate to Arconic Corporation common stock in a manner intended to preserve the aggregate intrinsic value of the original awards.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Diana Toman  (CLO and Corporate Secretary), by power of attorney</signatureName>
        <signatureDate>2020-04-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
