ITEM	Clay firebricks
	BN-40a	BN-40b
Al2O3, %	≥40		≥40
Fe2O3, %	≤1. 5		≤1. 8
Apparent Porosity，%	≤18		≤18
Refractoriness Under Load 0. 2Mpa，℃	≥1450		≥1400
Cold Crushing Strength，MPa	49. 0		34. 3
Linear Change after heating，%1400℃, 2h	+0～-0. 4		+0～-0. 4