PN series of mono block tapping hole bricks are made of scientifically and reasonably proportioned high purity electro-fused magnesite and high purity flake graphite as main material, adopting unique anti-oxidant and binding system and pressed by special process. They can be applied to all kinds of large, medium and small sized EAFs and convertors. This kind of products offers unique properties of good oxidization resistance, high hot/cold crushing strength, excellent corrosion and erosion resistance, etc. Especially, its excellent integrity effectively resolves the problems of property discrepancy and poor corrosion and erosion resistance on joints the assembled tapping hole encountered, which significantly improve the service life of tapping hole.