What MC-10, MC-14, MC-18 actually mean
- ▸The number after MC refers to the residual carbon content (%). MC-10 is ~10% carbon, MC-14 is ~14%, MC-18 is ~18%.
- ▸Higher carbon means better resistance to slag penetration (the slag wets carbon poorly) and better thermal-shock tolerance. It also means more carbon to oxidise above 1500 °C and lower mechanical strength of the matrix.
- ▸All three grades use fused or sintered magnesia as the primary aggregate, antioxidant additives (typically Al, Si, or Al-Mg alloy powder) and a phenolic resin binder.
- ▸The right grade is the lowest carbon content that survives your slag — because higher carbon costs more and oxidises faster.
Match grade to slag chemistry
- ▸If your slag basicity (CaO/SiO₂) sits consistently between 1.6 and 2.2 with FeO under 12%, MC-10 is usually sufficient — typical for cleaner steel grades and well-controlled secondary metallurgy.
- ▸If basicity is variable (1.4–2.8) or FeO runs in the 12–22% band, step up to MC-14. This is the most common spec for Pune-belt secondary steel and Indian induction-furnace shops with mixed scrap inputs.
- ▸If you're running EAF with aggressive arc-zone slag, FeO consistently above 22%, or hot-spot metal-line wear, MC-18 is justified. Don't use it as a default — the extra carbon is wasted on calmer slags.
Ladle size and tap practice matter too
- ▸Smaller ladles (15–25 t) cycle faster and see more thermal shock per unit campaign. MC-14 with good antioxidant package usually outperforms MC-10 here even on calm slags.
- ▸Larger ladles (50+ t) tolerate MC-10 in slag-line if the basicity is stable, because the per-heat thermal swing is smaller.
- ▸Long tap-to-tap times (>90 min) increase exposure to atmospheric oxidation. Step up grade or move to a better antioxidant package, not necessarily more carbon.
What to do before placing the order
- ▸Sample your slag — get basicity, FeO, MnO, SiO₂ from at least 5 heats spread across a campaign. Don't trust a single sample.
- ▸Map your wear by zone. If slag-line is failing 2× faster than metal-line, the answer is a slag-line ring upgrade — not a full-lining upgrade.
- ▸Audit your joint mortar. A premium MC brick with sloppy joints loses its advantage in 10 heats. Joint discipline is half the campaign-life equation.
- ▸Talk to your supplier about antioxidant package. MC-14 with Al-Mg antioxidant outperforms MC-14 with plain Al on long tap-to-tap practices.
Key takeaway
MC-14 is the right default for most Indian secondary-steel ladles. Step up to MC-18 only when arc-zone slag or high FeO justifies it. Step down to MC-10 only when slag chemistry is consistently calm. Always pair the grade with joint and antioxidant discipline.