CCM: Continuous Casting Machine

TL;DR

  • Purpose: Converting molten metal into ingots and billets
  • Technology: CCM (Continuous Casting Machine)
  • Throughput: 42 t Al + 11 t Fe-Mn steel → billets 100×100 mm
  • Key feature: NaK cooling (not water!), 100% local crystallizer materials

Overview

CCM is key equipment for converting liquid metal into solid billets. Melt from the tundish flows continuously into the crystallizer, where it solidifies and is drawn out as an ingot.

CCM Schematic

flowchart TD
    subgraph INPUT["INPUT"]
        TUNDISH["Tundish<br/>1500°C"]
    end

    subgraph CRYSTALLIZER["CRYSTALLIZER"]
        STOPPER["Stopper"]
        MOLD["Crystallizer<br/>100×100 mm"]
        COOLING["NaK cooling<br/>−150°C"]
    end

    subgraph PULLING["WITHDRAWAL"]
        ROLLERS["Withdrawal rolls<br/>0.5-1 m/min"]
        CUTTING["Gas cutting<br/>length 6 m"]
    end

    subgraph OUTPUT["OUTPUT"]
        BILLETS["Billets 100×100×6000 mm<br/>to roller table"]
    end

    TUNDISH --> STOPPER
    STOPPER --> MOLD
    MOLD --> COOLING
    COOLING --> ROLLERS
    ROLLERS --> CUTTING
    CUTTING --> BILLETS

    style INPUT fill:#f0e68c
    style CRYSTALLIZER fill:#fff3cd
    style PULLING fill:#d4edda
    style OUTPUT fill:#cce5ff

CCM Design

Crystallizers (two types)

The two CCMs use different crystallizer materials — both from local resources:

CCM-Al: Steel Crystallizer

Parameter Value
Material Fe-6%Mn steel (local)
Shape Square 100×100 mm
Length 800 mm
Coating MgO ceramic (prevents sticking)
Cooling NaK circuit

Why steel for Al? - Aluminum melts at 660°C, steel at 1538°C — ~900°C margin - Steel thermal conductivity ~50 W/(m·K) — lower than copper, but sufficient given large temperature gradient - 100% local material, no imports - MgO coating prevents aluminum adhesion

CCM-Fe: Ceramic Crystallizer

Parameter Value
Material MgO ceramic (magnite, local)
Shape Square 100×100 mm
Length 800 mm
Coating Not required (MgO is inert to Fe melt)
Cooling NaK circuit

Why MgO for Fe? - MgO melting point = 2852°C — ~1300°C margin above Fe melt (1538°C) - Thermal conductivity ~30-60 W/(m·K) — lower than copper, casting speed reduced (~0.3 m/min vs 1 m/min) - Inert to iron melt — does not form carbides (unlike graphite) - 100% local: magnesium is 8% of Mercury regolith, calcination → MgO - More frequent replacement (every 3-5 days), but material is unlimited

Earth analogs: MgO ceramics are a standard refractory in metallurgy. Used in tundishes, furnace linings, and casting equipment (Refratechnik, RHI Magnesita).

Why NaK instead of water? - Water freezes at −150°C outside the dome - NaK is liquid from −12°C to +785°C — works in any conditions - Closed cycle: NaK → radiators → return

Withdrawal Rolls

Parameter Value
Number of pairs 3-4
Withdrawal speed 0.5-1 m/min
Force per pair 5-10 tons
Roll material Steel with ceramic coating

Operating principle: 1. Melt enters the crystallizer 2. Shell solidifies on walls (crystallizer removes heat via NaK) 3. Rolls pull the ingot downward 4. Core solidifies as it moves

Plasma Cutting

The continuous ingot is cut into 6 m billets.

Parameter Value
Method Plasma cutting
Cutting frequency Every 6 minutes (at 1 m/min speed)
Plasma gas Ar (argon, ~1% of regolith)
Power ~50 kW (pulsed)

Advantages of plasma: - No carbon required (unlike oxy-acetylene) - Clean cut without oxidation - Argon extracted from regolith (100% localization)

Two CCMs at the Factory

The Ground Zero Factory is equipped with two CCMs:

CCM Metal Throughput Output
CCM-Al Aluminum 42 t/day Ingots 100×100×6000 mm
CCM-Fe Fe-Mn steel 11 t/day Billets 100×100×6000 mm

Roller table: A conveyor roller system transports ingots to the rolling mill.

Operating Modes

Continuous casting (main mode)

  • Tundish continuously supplies melt
  • CCM operates 20-22 hours/day
  • Stoppages: 2-4 hours for crystallizer replacement (every 5-7 days)

Emergency shutdown

If melt runs out or quality drops: 1. Tundish stopper closes 2. Rolls continue pulling until crystallizer is empty 3. CCM cools and is cleaned

Restart time: 1-2 hours

Quality Control

Parameter Control Norm Action on deviation
Melt temperature Pyrometer 1500±10°C Induction heating
Withdrawal speed Encoders on rolls 0.5-1 m/min Speed adjustment
Cracks on ingot IR camera No cracks Ingot rejection
Ingot size Laser profilometer 100×100±1 mm Stop and inspect

Automation: AI system analyzes ingot quality in real time and adjusts parameters.

Power Consumption

Component Power Purpose
NaK cooling (2× CCM) 50 kW × 2 Coolant pumps
Withdrawal rolls (2× CCM) 30 kW × 2 Electric motors
Gas cutting 10 kW Torches, gas supply
Roller table 20 kW Ingot transport
Automation 5 kW Sensors, control
TOTAL ~195 kW

Material Balance

Daily throughput:

Metal Input (melt) Output (ingots) Losses
Aluminum 41.5 t 41 t 1.2% (trim)
Fe-Mn steel 10.85 t 10.7 t 1.5% (trim)

Trim: Periodically remelted in the solar furnace and returned to the cycle.

Maintenance

Operation Frequency Performer
Crystallizer replacement 5-7 days Centaur-M (2 robots)
Roller table cleaning Daily Crab-M
Sensor calibration Weekly Automation
Roll replacement 1 month Centaur-M

Crystallizer replacement time: 2-4 hours (including cooling and disassembly).

See Also