Copper Mould Tube for Continuous Casting — CuAg0.1 and CuCrZr, Coated and Taper-Matched
The copper mould tube is the single component that sets how fast and how defect-free you can cast. It carries the heat flux that forms the solidifying shell at the meniscus, and its alloy, coating and taper geometry together determine casting speed, tube life, and breakout risk. We supply copper mould tubes in CuAg0.1 and CuCrZr alloy, with Ni-Cr or Ni-Co surface coating, machined to the taper profile and size matrix of your billet, bloom or slab caster — fully integrated with our continuous casting machine (CCM) spare parts engineering rather than sold as a generic commodity tube.
What Determines Mould Tube Performance?
Three critical engineering variables must be specified together rather than independently:
- Copper alloy — sets maximum heat flux capacity and resistance to softening under repeated thermal cycling.
- Surface coating — sets hot-face wear resistance and resistance to thermal-fatigue (craze) cracking.
- Taper geometry and wall thickness — sets how tightly the tube tracks shell shrinkage as the steel cools, and how the tube responds thermally over its service life.
Getting one of the three right and the other two wrong still produces short tube life, uneven shell growth, or a breakout.
Copper Alloy Grades — CuAg0.1 vs. CuCrZr
Alloy Technical Data (TDS)
| Property | CuAg0.1 (Silver Copper) | CuCrZr (Chromium-Zirconium Copper) |
|---|---|---|
| Electrical Conductivity | ≥98% IACS | 80–85% IACS |
| Thermal Conductivity | ≥385 W/m·K | 310–330 W/m·K |
| Softening Temperature | ~300°C | 450–500°C |
| Hardness (as supplied) | 90–110 HV | 130–160 HV |
| Typical Application | Billet / bloom, standard casting speed | Slab, high-speed / high-heat-flux casting |
Indicative industry ranges — certified Mill Test Certificates (MTC) govern the specific batch supplied.
Material Selection Guide: CuAg0.1 vs. CuCrZr by Casting Duty
CuAg0.1 carries more heat per unit area but softens at a lower temperature — fine for conventional casting speeds, but it loses dimensional stability faster under high-heat-flux, high-speed slab casting. CuCrZr trades a little conductivity for a much higher softening point, which is why high-speed slab casters specify it almost exclusively today.
Surface Coating Engineering — Ni-Cr and Ni-Co
Coating Technical Data (TDS)
| Property | Ni-Cr Coating | Ni-Co Coating |
|---|---|---|
| Typical Thickness | 0.10–0.15 mm | 0.30–1.0 mm (meniscus wear band) |
| Surface Hardness | 500–600 HV | 250–350 HV |
| Primary Function | General anti-stick / oxidation resistance over full tube length | Wear and thermal-fatigue resistance at the meniscus zone, where cracking starts |
| Typical Zone | Full working length | Meniscus band, sometimes full length on high-speed casters |
Failure Prevention: Why Coating Selection Dictates Tube Life
Most mould tube failures that get blamed on "bad copper" are actually coating failures — craze cracking at the meniscus from thermal-fatigue cycling, or spallation that exposes bare copper to abrasive wear from mould powder and oscillation. Coating selection and thickness at the meniscus band is often the highest-leverage spec decision on the whole tube.
Taper Profile and Size Range by Caster Type
Taper Geometry: Single, Parabolic & Multi-Taper Curves
Single-taper, parabolic, and multi-taper (segmented) profiles are matched to steel grade and casting speed — a taper cut for low-carbon steel will run a peritectic grade too loose at the corners, accelerating shell thinning and breakout risk at exactly the grade that's most breakout-prone to begin with.
Size Matrix by Caster Type
| Caster Type | Typical Section Size | Wall Thickness | Tube Length |
|---|---|---|---|
| Billet (square) | 80×80 to 180×180 mm | 12–18 mm | 700–900 mm |
| Billet (round) | Ø90 to Ø400 mm | 12–20 mm | 700–900 mm |
| Bloom | 200×200 to 400×500 mm | 16–24 mm | 800–1000 mm |
| Slab | 900–2700 mm width × 150–300 mm thickness | 14–28 mm | 800–1100 mm |
Confirm against your caster's actual drawing — we machine to your exact dimensions and taper curve, not a rounded-off standard size. For downstream finishing, discover our matched rolling mill rolls for continuous billet and section rolling.
Mould Tube Failure Analysis — Engineering Diagnostics
Field Failure Modes & Wear Mechanisms on CCM Lines
1. Meniscus Craze Cracking (Thermal Fatigue)
Fine crack networks at the meniscus band, from repeated thermal cycling as the meniscus level fluctuates — points to coating thickness or hardness mismatch at that zone, not the alloy.
2. Longitudinal Wall Cracking (Taper Stress)
A crack running down the tube length — usually a taper/section mismatch forcing uneven shell contact pressure against the wall, concentrating stress along one line.
3. Coating Spallation & Delamination
Coating lifting or flaking off in patches — exposes bare copper to direct abrasive and thermal exposure, and accelerates from that point outward once it starts.
4. Taper Wear & Bore Diameter Growth
Gradual loosening of fit against the shell over tube life — a wear-life expectation, not a defect, but one that should be tracked against a replacement schedule rather than run to breakout.
Quality Assurance & Pre-Shipment Inspection Protocol
Four-Stage Factory Verification Checklist
Acceptance Standards & Certified Testing:
- Dimensional inspection of bore taper profile along the full tube length, not just at three reference points
- Coating thickness measurement at meniscus band and full working length separately
- Alloy composition and hardness verification against the mill certificate
- Surface finish and bore roughness check on the hot face
Frequently Asked Questions: Copper Mould Tubes
What's the difference between CuAg0.1 and CuCrZr mould tubes?
CuAg0.1 has higher conductivity but softens at a lower temperature; CuCrZr trades some conductivity for a much higher softening point, which is why high-speed slab casters specify it.
How thick should the Ni-Cr or Ni-Co coating be?
It depends on the zone — a thin, hard Ni-Cr layer suits the general working length, while the meniscus band usually needs a thicker Ni-Co layer sized for thermal-fatigue resistance, not just hardness.
Can you machine the tube to match our existing taper curve exactly?
Yes — send us your current tube drawing or a worn sample for taper mapping, and we match the profile rather than supplying a standard catalog taper.
Why do our tubes crack at the meniscus specifically?
That almost always points to coating thickness or hardness at the meniscus band being mismatched to your casting speed and steel grade's thermal-fatigue demand, not the copper alloy itself.
Do you supply the full mould assembly, or just the tube?
This page covers the copper mould tube itself; copper plate (for slab moulds), foot rolls, segment rolls and other CCM wear parts are available on our CCM Spare Parts & Components page.
Engineering Consultation & Mould Tube RFQ
Send us your caster type, section size, current taper curve or tube drawing, and your steel grade mix. Our metallurgical engineering team will confirm alloy, coating, and taper profile against your actual operating parameters before quoting, backed by comprehensive Mill Test Certificates (MTC).
Related Continuous Casting Equipment & Components
- CCM Spare Parts & Components — Mould copper plates, segment rolls, guide rolls, bearings, and dummy bar assemblies for continuous casters.
- Rolling Mill Rolls — Work rolls and backup rolls for billet, bar, section, and plate mills downstream of casting.
- Tundish Refractory Solutions — Working linings, baffles, weirs, and flow control systems delivering molten steel into the mould tube.
- Tundish Nozzle Well Blocks & Metering Nozzles — Submerged entry nozzles (SEN) and seating blocks precisely aligned with the mould tube meniscus.
- Complete Steel Plant Refractory Solutions — Integrated refractory engineering and consumable packages from melting furnace to continuous caster.