Berkshire Hathaway will pay $235 per share. The deal is valued at about $37.2 billion, including debt.
"I've admired PCC's operation for a long time," Buffett, Berkshire Hathaway chairman and chief executive officer, said in a statement. "For good reasons, it is the supplier of choice for the world's aerospace industry, one of the largest sources of American exports."
Shares of Precision Castparts, which makes components such as industrial gas turbines and commercial airplane parts, surged in Monday premarket trading.
Berkshire Hathaway has roughly $67 billion in cash and faced pressure to use some of that capital to boost shareholder returns.