The graphite die is the heart of every horizontal and vertical continuous casting line. Its bore geometry, surface finish, and graphite grade determine product diameter tolerance, surface quality, and die life. As a graphite die supplier in India, Expo Advanced Materials machines precision dies from extruded graphite billets for copper, brass, bronze, and aluminium continuous casting operations worldwide.
Why Extruded Graphite for Casting Dies?
Extruded graphite is preferred over isostatic graphite for casting dies because the grain orientation runs parallel to the casting direction, giving the bore surface superior tribological properties — lower friction against the solidifying metal and better resistance to thermal fatigue cracking. The anisotropic structure also improves axial thermal conductivity, helping extract heat from the solidification front.
Metals We Supply Dies For
| Metal | Casting Temp (°C) | Bore Finish (Ra) | Recommended Grade |
|---|---|---|---|
| Electrolytic tough pitch copper | 1,085–1,150 | ≤ 0.4 μm | EG-grade extruded |
| Brass (CuZn) | 900–1,050 | ≤ 0.8 μm | EG-grade extruded |
| Bronze (CuSn, CuAl) | 950–1,050 | ≤ 0.8 μm | Dense extruded |
| Aluminium and alloys | 660–750 | ≤ 1.6 μm | Fine-grain extruded |
Dimensions and Tolerances
- Bore diameter: 6 mm to 250 mm (circular); rectangular and special profiles on request
- Die length: 100–800 mm
- Bore roundness: ≤ 0.01 mm for copper-grade dies
- Bore cylindricity: ≤ 0.02 mm over die length
- OD tolerance: ±0.05 mm for water-jacket fit
- Special profiles: Round-cornered square, flat bar, and bus-bar profiles available
Die Life and Maintenance
Graphite die life depends on metal type, casting speed, cooling water quality, and withdrawal force. Typical copper die life: 3–8 tonnes cast per die before bore diameter exceeds tolerance. We offer a die re-bore service to extend service life before replacement, and maintain dimensional records for each die serial number.
How to Order
Provide bore diameter (or cross-section profile), die length, metal being cast, required bore finish, and quantity. Drawings in DXF or PDF format accepted. Standard copper dies: 15–20 working days from order. Rush orders on common sizes in 7–10 days.