UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

January 4, 2013

Date of Report (Date of earliest event reported)

PRECISION CASTPARTS CORP.

(Exact name of registrant as specified in its charter)

4650 S.W. Macadam Avenue

Suite 400

Portland, Oregon 97239-4254

(Address of principal executive offices, including zip code)

(503) 946-4800

(Registrant’s telephone number, including area code)

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

As previously disclosed, on November 9, 2012, Titanium Metals Corporation, a Delaware corporation (the “Company”), Precision Castparts Corp. (“Parent”) and ELIT Acquisition Sub Corp. (“Purchaser”), a wholly owned subsidiary of Parent, entered into an Agreement and Plan of Merger (the “Merger Agreement”). Pursuant to the Merger Agreement, and upon the terms and subject to the conditions thereof, Purchaser commenced a tender offer to purchase all outstanding shares of the common stock of the Company (the “Shares”) at a price of $16.50 per Share, net to the seller in cash, without interest thereon and less any required withholding of taxes, upon the terms and subject to the conditions set forth in the Offer to Purchase dated November 20, 2012 (as amended or supplemented, the “Offer to Purchase”), and the related Letter of Transmittal (which, together with the Offer to Purchase, constituted the “Offer”).

The Offer, as extended, expired at 5:00 p.m., New York City time, on December 20, 2012, following which Purchaser commenced a subsequent offering period of the Offer to acquire all remaining untendered Shares. The subsequent offering period of the Offer expired at 5:00 p.m., New York City time, on January 4, 2013. Together with the Shares purchased in the initial offering period, Purchaser owned 158,231,903 Shares (representing approximately 90.4% of the outstanding Shares) as of the expiration of the subsequent offering period.

On January 7, 2013, pursuant to the terms and conditions of the Merger Agreement, Purchaser merged with and into the Company (the “Merger”) with the Company surviving the Merger as a wholly owned subsidiary of Parent. At the effective time of the Merger, all remaining outstanding Shares not tendered in the Offer (other than Shares owned by Parent, Purchaser or the Company or Shares held by Company stockholders, if any, who are entitled to and properly exercise appraisal rights under Delaware law), were acquired for cash at the same $16.50 per Share price, without interest and subject to applicable withholding taxes, that was paid in the Offer.

The foregoing discussion of the Merger Agreement and the transactions contemplated thereby does not purport to be complete and is subject to, and qualified in its entirety by, the full text of the Merger Agreement, a copy of which is included as Exhibit 2.1 hereto and incorporated herein by reference.

On January 7, 2013, Parent issued a press release announcing the completion of the subsequent offering period, a copy of which is included as Exhibit 99.1 to this Current Report on Form 8-K and incorporated herein by reference. On January 8, 2013, Parent issued a press release announcing the completion of the Merger, a copy of which is included as Exhibit 99.2 to this Current Report on Form 8-K and incorporated herein by reference.

(d) Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

EXHIBIT INDEX