<SEC-DOCUMENT>0000842633-13-000139.txt : 20130618
<SEC-HEADER>0000842633-13-000139.hdr.sgml : 20130618
<ACCEPTANCE-DATETIME>20130618173022
ACCESSION NUMBER:		0000842633-13-000139
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20130614
FILED AS OF DATE:		20130618
DATE AS OF CHANGE:		20130618

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TRIMAS CORP
		CENTRAL INDEX KEY:			0000842633
		STANDARD INDUSTRIAL CLASSIFICATION:	METAL FORGING & STAMPINGS [3460]
		IRS NUMBER:				382687639
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		39400 WOODWARD AVENUE, SUITE 130
		CITY:			BLOOMFIELD HILLS
		STATE:			MI
		ZIP:			48304
		BUSINESS PHONE:		2486315400

	MAIL ADDRESS:	
		STREET 1:		39400 WOODWARD AVENUE, SUITE 130
		CITY:			BLOOMFIELD HILLS
		STATE:			MI
		ZIP:			48304

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Tredwell Daniel P
		CENTRAL INDEX KEY:			0001399401

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10716
		FILM NUMBER:		13920335

	MAIL ADDRESS:	
		STREET 1:		55 RAILROAD AVENUE
		STREET 2:		1ST FLOOR
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_137159101291343.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2013-06-14</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000842633</issuerCik>
        <issuerName>TRIMAS CORP</issuerName>
        <issuerTradingSymbol>TRS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001399401</rptOwnerCik>
            <rptOwnerName>Tredwell Daniel P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>177 BROAD STREET</rptOwnerStreet1>
            <rptOwnerStreet2>10TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>STAMFORD</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06901</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>2013-06-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20173</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>32.66</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2144970</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2013-06-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20173</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>32.66</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2144970</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3448</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">On June 14, 2013, TriMas Investment Fund I, L.L.C. (&quot;TIF I&quot;) purchased 16,152 and 4,021 shares of common stock of the Issuer (&quot;Common Stock&quot;) from HIP Side-by-Side Partners, L.P. (&quot;Side-by-Side&quot;) and TriMas Investment Fund II, L.L.C. (&quot;TIF II&quot;), respectively.</footnote>
        <footnote id="F2">TIF I directly owns 1,131,513 shares of Common Stock; Metaldyne Investment Fund I, L.L.C. (&quot;MIF I&quot;) directly owns 847,033 shares of Common Stock; Side-by-Side directly owns 133,247 shares of Common Stock; TIF II directly owns 20,738 shares of Common Stock; and Metaldyne Investment Fund II, L.L.C. (&quot;MIF II&quot;) directly owns 12,439 shares of Common Stock.  The Reporting Person is the Managing Member of Heartland Industrial Associates, L.L.C. (&quot;Heartland&quot;), which is the General Partner of Heartland Industrial Partners, L.P., which is TIF I's and MIF I's Managing Member.  Heartland is the managing member of TIF II and MIF II, and is the General Partner of Side-by-Side.  The Reporting Person disclaims beneficial ownership (as defined in Rule 16a-1(a)(2)) of these securities except to the extent of his pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Paula Reno attorney-in-fact</signatureName>
        <signatureDate>2013-06-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
