Nifco Inc. bought out its two overseas partners in plastic parts ventures and turned them into subsidiaries this week.

Nifco, a leading maker of industrial plastic parts and components, said it bought 50 percent of ITW-Nifco, based in Ohio, and 48.5 percent of Snipgrove Ltd., based in Stockton-on-Tees, Britain, from its partner, Illinois Tool Works Inc. With the deals, Nifco now owns 100 percent of ITW-Nifco and 97 percent of Snipgrove. ITW-Nifco was established in 1986 and Snipgrove in 1990, both through the partnership with Illinois Tool Works.

Nifco aims to hasten decision-making in its U.S. and British operations to cope with the rapidly changing needs of Japanese-affiliated automakers in the two countries, the firm's major customers. The buyouts, which cost the company 7.54 billion yen, will not affect Nifco's performance forecasts in the current business year that ends in March 1998, the firm said.