<SEC-DOCUMENT>0001209191-24-001028.txt : 20240105
<SEC-HEADER>0001209191-24-001028.hdr.sgml : 20240105
<ACCEPTANCE-DATETIME>20240105163025
ACCESSION NUMBER:		0001209191-24-001028
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20240103
FILED AS OF DATE:		20240105
DATE AS OF CHANGE:		20240105

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			NEWMAN DONALD P
		CENTRAL INDEX KEY:			0001282236
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12001
		FILM NUMBER:		24516661

	MAIL ADDRESS:	
		STREET 1:		224 S 108TH AVENUE
		CITY:			OMAHA
		STATE:			NE
		ZIP:			68154

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>2024-01-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001282236</rptOwnerCik>
            <rptOwnerName>NEWMAN DONALD P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ATI INC.</rptOwnerStreet1>
            <rptOwnerStreet2>2021 MCKINNEY AVE., SUITE 1100</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP and CFO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.10 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2024-01-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10423</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>149327</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>2024-01-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2016</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>43.19</value>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>147311</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>2024-01-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10355</value>
                    <footnoteId id="F5"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>43.56</value>
                    <footnoteId id="F6"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>136956</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Award of restricted stock units, which are settled in shares of stock upon vesting.  The award vests in three equal annual installments on each of the first three anniversaries of the grant date.</footnote>
        <footnote id="F2">Awarded under ATI's 2022 Incentive Plan.</footnote>
        <footnote id="F3">Shares withheld for the payment of taxes on restricted stock units that vested on January 3, 2024.</footnote>
        <footnote id="F4">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 3, 2024.</footnote>
        <footnote id="F5">Shares withheld for the payment of taxes on restricted stock units that vested on January 4, 2024.</footnote>
        <footnote id="F6">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 4, 2024.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Amanda J. Skov, Attorney-in-Fact for Donald P. Newman</signatureName>
        <signatureDate>2024-01-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
