PN series of EAF roofs/deltas show the features of high strength, excellent thermal shock resistance, corrosion resistance, consistent quality and long service life, etc. The products have been successfully applied in No. 3 steel Mill of Shanghai, Sha Steel, Lai Steel and Ben Steel, etc. The service life of the EAF roof for 90t EAF of Runzhong is over 200 heats, longer than that of imported EAF roofs, which only achieve 150 heats.