<SEC-DOCUMENT>0001033427-18-000014-index.html : 20180206
<SEC-HEADER>0001033427-18-000014.hdr.sgml : 20180206
<ACCEPTANCE-DATETIME>20180206091248
ACCESSION NUMBER:		0001033427-18-000014
CONFORMED SUBMISSION TYPE:	SC 13G/A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20180206
DATE AS OF CHANGE:		20180206

SUBJECT COMPANY:	

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

	FILING VALUES:
		FORM TYPE:		SC 13G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-46715
		FILM NUMBER:		18576336

	BUSINESS ADDRESS:	
		STREET 1:		1000 SIX PPG PLACE
		CITY:			PITTSBURGH
		STATE:			PA
		ZIP:			15222
		BUSINESS PHONE:		4123942800

	MAIL ADDRESS:	
		STREET 1:		100 SIX PPG PLACE
		CITY:			PITTSBURGH
		STATE:			PA
		ZIP:			15222

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALLEGHENY TELEDYNE INC
		DATE OF NAME CHANGE:	19960716

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			IRIDIAN ASSET MANAGEMENT LLC/CT
		CENTRAL INDEX KEY:			0001033427
		IRS NUMBER:				061439577
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A

	BUSINESS ADDRESS:	
		STREET 1:		276 POST ROAD WEST
		CITY:			WESTPORT
		STATE:			CT
		ZIP:			06880-4704
		BUSINESS PHONE:		2033417800

	MAIL ADDRESS:	
		STREET 1:		276 POST ROAD WEST
		CITY:			WESTPORT
		STATE:			CT
		ZIP:			06880-4704
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G/A
<SEQUENCE>1
<FILENAME>allegheny13ga112312017.htm
<TEXT>
Document 1 - file: allegheny13ga112312017.htm

</DOCUMENT>
</SEC-DOCUMENT>