With the development of con-casting technology, tube changers have been applied for the tundish in steel mills home and abroad. So we have developed the slide gate series products for tube changers, including porous upper nozzle, porous top and bottom plates, which have performed well in tube changers of Benxi Steel, second works of Anshan Steel, Taiyuan steel as well as foreign tube changers. Item Slide Plate Porous Upper Nozzle Plate Porous insert Nozzle Liner Porous Insert Al2O3 (%)≥ 72 90 82 90 ZrO2 (%)≥ 6 4 3.5 4.0 C (%)≥ 7 Cr2O3≥2% A.P. (%)≤ 3.05 3.05 B.D. (g/cm3) ≥ 120 C.C.S (Mpa) ≤10 20-22 ≤19 21-23 HMOR (Mpa) ≥ (1400°Cx0.5h) 12 Permeability (0.1 Mpa) ≥30L/min ≥20L/min