Blast furnace is iron making plant using ores and cokes as fuel to its hot blast which is approximately 1,200 °C . Pig iron is the crude, metallic product of an iron blast furnace, the basis of the whole iron and steel industry, and used for the steel plates of automobiles, ships, etc.

POSCO E&C has built all blast furnaces of POSCO's. In 1999 POSCO E&C successfully completed No.5 Blast Furnace at Gwangyang Steelworks and revamping of No.2 and No.3 Blast Furnaces at Pohang Steelworks and No.1, No.2 and No.3 Blast Furnaces at Gwangyang Steelworks using POSCO E&C's own technologies and know-hows.

Furthermore, POSCO E&C is to revamp No.4 Blast Furnace at Gwangyang Steelworks, the largest blast furnace in Korea and to build IISCO's blast furnace in India .

POSCO E&C has been stepping forward to be one of the world's leading companies in the area of blast furnace engineering based on its own technologies and know-how from its prior construction projects of blast furnaces.