Tanghan Steel has purchased a 10% share in Switzerland's Duferco International Trading Holding, underscoring the efforts of China to export more steel due to domestic overcapacity.

Tanghan, part of Hebei Group, the largest steelmaker in the Asian country, signed last week a deal that provides exclusive right to Duferco to sell Tanghan steel outside Asia, two sources familiar with the matter said.

Duferco chief executive Matthew De Morgan said told Reuters during a phone interview that the deal would boost their product portfolio as they expect substantial gain in volumes from the agreement.

Duferco International Trading Holding is a subsidiary of Duferco, a privately-owned group that ranks as one of the largest steel trading and producing companies in the world.