June 22 (Reuters) - Qatar's sovereign wealth fund is investing $75 million in Doncasters Group, a manufacturer of precision aviation components, ahead of its planned initial public offering on the U.S. stock exchange.

According to a disclosure filed with the U.S. Securities and Exchange Commission on Monday, the Qatar Investment Authority has agreed to purchase the shares at the initial public offering price.

The disclosure showed that, based on the average price range for the initial public offering, the Qatar Investment Authority would acquire approximately 2.5 million ordinary shares through the private placement.

The company, which is based in Derby, UK, is seeking to raise up to $746.7 million through an initial public offering by offering 23.3 million shares at a price between $28 and $32 per share.

If the IPO is priced at the top end of the price range, the aviation parts manufacturer's market capitalization will be $4.51 billion based on the outstanding shares referred to in the disclosure.

Doncasters manufactures a wide range of complex parts, including blades and fins, for aviation engines and industrial gas turbines.

The investment by Qatar's sovereign wealth fund comes in addition to a concurrent private placement, in which some existing shareholders, including board members, agreed to purchase $66 million worth of shares in Doncasters.

Jefferies and Morgan Stanley will be joint bookrunners. Doncasters shares will be listed on the New York Stock Exchange under the symbol (DPC).