Y-FB       GFB40        GFB42       GFB45 

Al2O3(%)min.                                                     40           40            42            45    

  Fe2O3(%)max.                                               2.5

  Refractoriness()min.                                      1710         1730          1750          1750        

  Refractoriness under load 0.2MPa()min.        1300         1350          1400          1400        

  Apparent porosity(%)max.                               22            20              20              20          

  Cold crushing strength (MPa)min.                    30            30              35              40        

Linear change after reheating(%)max.         

                     At 1350×2h                               +0.1

                                                                       -0.4

                    At1400X3h                                             +0.1        +0.1           +0.2                                        

                                                                                - 0.5           -0.4           -0.2