| 摘要 |
Disclosed is a magnesia-carbon based sleeve brick for steelmaking converters, which is obtained by adding, to a refractory raw material mix containing 60 to 95 mass% of a magnesia raw material and 5 to 20 mass% of graphite, a metal powder of one or more selected from the group consisting of Al, Si, Mg, Ca, Cr and an alloy thereof, in an amount of greater than 3 to 6 mass%, and an organic binder, in addition to 100 mass% of the refractory raw material mix, and subjecting the resulting mixture to kneading, forming and heat treatment, wherein the sleeve brick is used under a condition that a thickness thereof is set at 70 mm or less. This makes it possible to prevent cracking which would otherwise occur in the sleeve brick itself, to allow the sleeve brick to have enhanced durability. One or more selected from the group consisting of B, B 4 C, MgB 2 , CaB 6 and CrB may be further added in an amount of 0.1 to 3 mass%, in addition to 100 mass% of the refractory raw material mix, to enhance strength and oxidation resistance and further enhance the durability. The magnesia raw material may comprise a first particle fraction having a particle diameter of greater than 10 to 500 µm and occupying 20 to 50 mass% in the refractory raw material mix, and a second particle fraction having a particle diameter of 10 µm or less and occupying 5 mass% or less in the refractory raw material mix, to additionally enhance corrosion resistance and thermal shock resistance. |
