Alu Pak 73 Cr · DoruPlast 90 IND
Furnace Patching Material
Chrome-based and high-alumina patching materials for fast furnace repairs — 300 kg to 5 ton furnaces.
Furnace patching materials repair worn or eroded spots in a lining without a full reline, extending campaign life on smaller furnaces. DFP India supplies two grades for 300 kg to 5 ton induction furnaces: Alu Pak 73 Cr, a chrome-based patching material, and DoruPlast 90 IND, a high-alumina material with a fine 0–1 mm grain size. Both let you patch localised wear quickly and get the furnace back into production.
1750–1800 °C
Max. service temperature
300 kg–5 t
Furnace size range
2 grades
Chrome-based & high-alumina
Performance & consumption
| Product | Base | Al₂O₃ | Grain size | Max. service temp. | Supply / bonding |
|---|---|---|---|---|---|
| Alu Pak 73 Cr | Fused corundum + chrome (≈4% Cr₂O₃) | 75% | 0–3 mm | 1750 °C | Phosphate-bonded |
| DoruPlast 90 IND | High-alumina | 92% | 0–1 mm | 1800 °C | Wet, ready to use |
Case in point
Patching localised wear without a full reline
On smaller induction furnaces, localised erosion doesn't always warrant a full reline. DFP India's patching grades — chrome-based Alu Pak 73 Cr and high-alumina DoruPlast 90 IND — let a crew repair worn spots on 300 kg to 5 ton furnaces and return to melting quickly, extending the usable life of the lining.
Competitive edge vs. generic / local
- Two patching grades — chrome-based Alu Pak 73 Cr and high-alumina DoruPlast 90 IND — to match the repair and the metal being melted.
- Fine 0–1 mm grain size on DoruPlast 90 IND for tight, well-bonded patches.
- Sized for 300 kg to 5 ton induction furnaces, where quick localised repairs matter most.
What changes when you switch
| Aspect | Full reline | DFP patching |
|---|---|---|
| Downtime | Furnace out of service for a full reline | Localised patch — back in production quickly |
| Material use | Whole lining replaced | Only the worn area repaired |
| Grade choice | One lining material | Chrome-based or high-alumina to suit the repair |
Frequently asked questions
What are Alu Pak 73 Cr and DoruPlast 90 IND used for?
Both are patching materials for repairing worn or damaged areas of a furnace working lining without a full reline. They are used on coreless (crucible) and channel induction furnaces — DFP India supplies them for roughly 300 kg to 5 ton furnaces — and also to repair spouts and top caps in steel and iron foundries. Alu Pak 73 Cr can additionally serve as a top-cap and spout material and for maintenance of steel ladle linings.
What is the difference between Alu Pak 73 Cr and DoruPlast 90 IND?
Alu Pak 73 Cr is a fused-corundum, chrome-bearing (≈4% Cr₂O₃), phosphate-bonded patching material with a coarser 0–3 mm grain — the chrome addition gives strong erosion and abrasion resistance for severe steel-melting duty. DoruPlast 90 IND is a high-alumina (92% Al₂O₃) material with a fine 0–1 mm grain, supplied wet and ready to use — ideal for thin, fine surface repairs on working linings and spouts.
Which grade should I use for severe erosion or abrasion?
Alu Pak 73 Cr. Its chromium-oxide addition gives good erosion and abrasion resistance, which suits severe applications in steel-melting coreless furnaces.
Which grade is best for fine or thin surface repairs?
DoruPlast 90 IND. Its fine 0–1 mm grain size is made for repairing damaged, thin-section surfaces on working linings and spouts.
Do I need to mix these, or are they ready to use?
DoruPlast 90 IND is supplied wet and ready to use — it can be trowelled straight on with no mixing. Alu Pak 73 Cr is a phosphate-bonded patching material applied by patching/trowelling.
What is the maximum service temperature?
Alu Pak 73 Cr is rated to 1750 °C; DoruPlast 90 IND to 1800 °C.
What is the chemical composition?
Alu Pak 73 Cr: about 75% Al₂O₃, 9% SiO₂, 4% Cr₂O₃ and 3.5% P₂O₅, with a bulk density around 2.85 g/cm³. DoruPlast 90 IND: about 92% Al₂O₃ and 4% SiO₂, with low Fe₂O₃ (≈0.3%).
How should they be stored, and what is the shelf life?
Store both in a dry place and keep them from freezing. Use Alu Pak 73 Cr within 6 months for best workability; DoruPlast 90 IND keeps for about 12 months — keep the buckets well closed and frost-free.