Corundum Brick Manufacturer for 1750°C Steel & Furnace Zones

Corundum brick is the material you specify when the failure mechanism is chemical attack or sustained high temperature, and thermal shock is not the dominant concern. Built on high-purity fused or sintered corundum at 95–99% Al₂O₃, it has very little impurity left to form low-melting phases with slag, which is precisely why it resists penetration where lower-alumina materials slowly dissolve.

What Purity Actually Buys You

In alumina-based refractories, the enemy is usually not the alumina — it is everything else. Silica, iron oxide and alkali impurities combine with slag components to form eutectics that melt well below the service temperature, and the brick then loses its hot face from the inside out. Holding Fe₂O₃ to 0.3% and total Al₂O₃ to 95–99% removes most of that pathway. The brick becomes chemically inert against a much wider range of slags, and penetration depth drops accordingly.

This is why we test and report impurity levels, not just alumina content. Two bricks both labelled "90% alumina" can behave very differently in service depending on what the remaining 10% is.

Where Corundum Is the Right Choice

• Blast furnace hearth and ceramic cup — resistance to iron penetration plus volume stability under sustained load.
• Tuyere and hearth assemblies — high density and crushing strength where mechanical and thermal load coincide.
• Ladle bottoms, well blocks and seats — high-wear zones with slag contact.
• Reheating and heat treatment furnaces — skid rails, burner surrounds and hot zones.
• Carbon black reactors, gasifiers, incinerators — severe wear with corrosive atmospheres.

Where It Is Not

Two honest caveats. First, thermal shock resistance falls as purity rises — a 99% alumina brick cycled rapidly will spall before an 80% brick will. If your zone cycles, use corundum-mullite or mullite instead. Second, strongly basic slags (high CaO, BOF and ladle slag lines) attack alumina; for those zones specify magnesia-carbon, AMC or a spinel-bearing grade. Corundum is not a universal upgrade, and any supplier who tells you otherwise is selling, not specifying.

Manufacturing and Machining

XZK corundum bricks are pressed on 2,000-ton class CNC hydraulic presses from high-purity fused and sintered corundum and fired in computer-controlled ultra-high-temperature kilns. Over 60% of output is made to customer drawings. Dimensional tolerance on machined seating faces is held to ±1.0 mm, and critical assemblies such as tuyere combinations and well blocks are dry trial-fitted before shipment so that site grinding is minimised.

Quality and Documentation

Bulk density and apparent porosity per ASTM C830, cold crushing strength per ASTM C133, chemical analysis per GB/T 6900 and refractoriness per ISO 528 are tested per batch, and a Certificate of Analysis ships with every lot. SGS, BV or TÜV inspection with witnessed sampling can be arranged. Send your drawing or wear-zone details for a grade recommendation and quotation within 48 hours.

Where This Grade Sits in the Lining System

Corundum and high-alumina grades earn their place on hot strength and creep resistance, and those properties only pay back if the surrounding zones survive as long as they do. Putting the strongest brick into the harshest zone and leaving the rest to habit is how most of the refractory budget is actually lost.

XZK supplies corundum brick as one zone of a zoned package rather than as a standalone item: the grades normally zoned alongside it — among them corundum mullite brick — are documented on the corundum and high-alumina refractories page, and the vessel-level architecture — where each zone starts and ends, and which mechanism actually limits the campaign — is set out on the blast furnace and steel ladle and RH/VD pages.

Campaign data measured on this class of lining — including the wear profile that drove grade selection — is published in the MMK Magnitogorsk No.10 BF and 375 t ladle programme project reference.