HIGH-DURABILITY SLEEVE BRICKS

A magnesia-carbon sleeve brick for steelmaking converters which has a thi ckness of 70mm or below and which is protected from the breakage of the bric k itself and improved in the durability, made by adding a metal powder of at least one member selected from the group consisting of Al, Si, Mg, Ca, Cr a nd alloys of these metals in an amount exceeding 3% by mass and up to 6% by mass in outer percentage and an organic binder to a refractory raw material composition comprising 60 to 95% by mass of a magnesia raw material and 5 to 20% by mass of graphite, and subjecting the obtained mixture to kneading, m olding and then heat treatment. The sleeve brick can be further improved in strength and oxidation resistance and thereby additionally enhanced in durab ility by further adding one or more of B, B4C, MgB2, CaB6 and CrB in an amou nt of 0.1 to 3% by mass in outer percentage. Further, the brick can exhibit enhanced corrosion resistance and thermal shock resistance, when particles o f the magnesia raw material having particle diameters exceeding 10.mu.m and up to 500.mu.m account for 20 to 50% by mass of the refractory raw material composition and particles thereof having particle diameters of 10.mu.m or be low account at most 5% by mass of the refractory raw material composition.