<SEC-DOCUMENT>0001209191-24-001444.txt : 20240111
<SEC-HEADER>0001209191-24-001444.hdr.sgml : 20240111
<ACCEPTANCE-DATETIME>20240111161544
ACCESSION NUMBER:		0001209191-24-001444
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20240109
FILED AS OF DATE:		20240111
DATE AS OF CHANGE:		20240111

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Harris Timothy J
		CENTRAL INDEX KEY:			0001776844
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12001
		FILM NUMBER:		24529435

	MAIL ADDRESS:	
		STREET 1:		C/O ALLEGHENY TECHNOLOGIES INCORPORATED
		CITY:			PITTSBURGH
		STATE:			PA
		ZIP:			15222

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ATI INC
		CENTRAL INDEX KEY:			0001018963
		STANDARD INDUSTRIAL CLASSIFICATION:	STEEL PIPE & TUBES [3317]
		ORGANIZATION NAME:           	04 Manufacturing
		IRS NUMBER:				251792394
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2021 MCKINNEY AVENUE
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75201
		BUSINESS PHONE:		4123942800

	MAIL ADDRESS:	
		STREET 1:		2021 MCKINNEY AVENUE
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75201

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALLEGHENY TECHNOLOGIES INC
		DATE OF NAME CHANGE:	19991213

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALLEGHENY TELEDYNE INC
		DATE OF NAME CHANGE:	19960716
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2024-01-09</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001018963</issuerCik>
        <issuerName>ATI INC</issuerName>
        <issuerTradingSymbol>ATI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001776844</rptOwnerCik>
            <rptOwnerName>Harris Timothy J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ALLEGHENY TECHNOLOGIES INCORPORATED</rptOwnerStreet1>
            <rptOwnerStreet2>1000 SIC PPG PLACE</rptOwnerStreet2>
            <rptOwnerCity>PITTSBURGH</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>15222</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior VP and CDIO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.10 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2024-01-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>74309</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>148196</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.10 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2024-01-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>32540</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>42.44</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>115656</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Settlement of performance-vested restricted stock units that were granted in 2021, the vesting of which was contingent upon the Issuer's total shareholder return relative to a specified peer group during the period from January 1, 2021 through December 31, 2023 (the &quot;2021-2023 PSUs&quot;). The shares underlying the 2021-2023 PSUs became payable as of January 9, 2024 following certification of the Issuer's achievement of the relevant performance criteria by the Compensation and Leadership Development Committee of the Issuer's Board of Directors.</footnote>
        <footnote id="F2">Shares withheld for payment of taxes in connection with the January 9, 2024 settlement of the 2021-2023 PSUs.</footnote>
        <footnote id="F3">Represents the average of the high and low trading prices for one share of the Issuer's common stock on the New York Stock Exchange on January 9, 2024.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Amanda J. Skov, Attorney-in-Fact for Timothy J. Harris</signatureName>
        <signatureDate>2024-01-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
