Chemial and Physical Properties		Precast Blocks for EAF Roof
		BDL-80	BDL-75
AL2O3,		80 min	75min
Refractory ℃		1790min	1790min
0.2Mpa Refractoriness ℃		1550	1530
Porosity,%	Roof brick    not more than	16	16
	Arch angle brick not more than	18	18
Room temperature compressive strength Mpa          not less than		60	60
Bulk/density  g/cm3                    not less than		3.0	2.9
Thermal shock resistance（1100℃ room temperature）,per time  not less than		8