Low Cement Castables (LCC)

A low cement castable is a monolithic refractory containing only 3–5% calcium aluminate cement binder, far less than the 15–30% in conventional castables. The reduced cement content gives much higher hot strength, lower porosity, better slag resistance and improved thermal shock performance. LCC is widely used in steel ladles, tundish permanent linings, torpedo cars and reheating furnaces.

Conventional castable: 15–30% cement, easy install, moderate hot strength, used in backup and non-critical zones. LCC: 3–5% cement, higher density and slag resistance, used in working linings of ladles and high-duty zones. ULCC (ultra-low cement): about 0.5–2% cement, highest density and hot strength, used in critical wear zones. The lower the cement, the longer the dry-out and the higher the price.

A typical 200–300 mm thick LCC lining requires a controlled dry-out of 24–72 hours. A typical schedule: ambient to 110°C at 20°C/hr, hold 12 hours, then 15°C/hr to 300°C, hold 8 hours, then 30°C/hr to operating temperature. Always follow the manufacturer curve for the grade and lining thickness. Skipping dry-out causes steam explosion (spalling), the single most common failure of new castable linings.

Modern 70–80% Al₂O₃ LCC ladle working linings deliver 80–140 heats between relines depending on steel grade, holding time, slag chemistry and ladle furnace use. Slag-line areas wear faster and are usually patched with gunning at 30–50 heat intervals. Argon-purging and electrode arcing zones may need spot repair every 15–20 heats.

We supply 60% Al₂O₃ LCC for tundish and general ladle backup, 70% Al₂O₃ LCC for standard ladle working linings, 80% Al₂O₃ LCC with spinel addition for premium ladle and steel-treatment work, and 85% Al₂O₃ LCC (LCC-85) for the highest-duty zones; self-flow versions are available for congested sections. Authorised CUMI dealer; Calderys grades also supplied.

Standard LCC is installed by vibration casting. For gunning and shotcreting, use a specifically-formulated LCC-gunning blend or a self-flow LCC, these have modified particle size distributions and additives. Mixing standard cast LCC with high water and gunning it gives poor density and short life. Always check the data sheet for the recommended placement method.

Accmon 70 (Ace Calderys) and Tata Cast LC 70 (TRL Krosaki) are competitor trade names for the same low cement castable specification as CUMI's HC 70, which we supply as our LCC-70 grade (68–72% Al₂O₃). See the full CUMI vs. competitor cross-reference table above for the rest of the HCS to HC 95 range.

Excel Cast (OCL) and Refcast LC (Sharadaa) are competitor trade names for the same low cement castable line as CUMI's HC series, which we supply as our LCC-60 to LCC-85 grades. Match by alumina percentage rather than by name, for example Excel Cast 70 B and Refcast LC 70 both correspond to our LCC-70 (68–72% Al₂O₃).