Japan's Hitachi Ltd said on Wednesday it would sell its listed chemicals unit and diagnostic imaging business in a deal totalling 673 billion yen ($6.2 billion), as the Japanese industrial conglomerate overhauls its business portfolio.

Hitachi will sell its 51% stake in Hitachi Chemical for 494 billion yen to Showa Denko. Hitachi Chemical is a supplier of materials for semiconductors, displays and lithium-ion batteries. Showa Denko said it was offering to pay a total of 964 billion yen for shares in Hitachi Chemical, including from Hitachi as well as the market.

Showa Denko beat rival bids from Nitto Denko Corp, US buyout funds Bain Capital LP and Carlyle Group LP. Hitachi's diagnostic imaging business will be sold to Fujifilm Holdings Corp for 179 billion yen as the Japanese photocopier and camera manufacturer deepens its push into healthcare.

The deal follows a recent series of acquisitions by Fujifilm, including a drugmaking business from US-based Biogen Inc and two biotechnology units from JXTG Holdings Inc as growth at its legacy photocopy business stagnates.

Hitachi has been among the most aggressive of Japan's conglomerates in reorganising its business, selling non-core assets while buying foreign businesses to expand digital businesses. The Japanese government has also pointed out potential conflicts of interest between publicly traded parent companies and their listed subsidiaries and set corporate governance guidelines for those companies. Hitachi expects the sale to generate 389 billion yen in special profits.