Xinda AT‑100D Alcohol‑Based Casting Coating Effectively Solves Inner‑Surface Burning‑On Defects of Duplex‑Steel Impeller
2026-08-20 09:21Xinda AT‑100D alcohol‑based casting coating developed by Liaoning Xinda Foundry Technology Co., Ltd. has completed application verification in the production of double‑deck closed impellers at a foundry. Aiming at external and internal burning‑on defects caused by high‑temperature pouring and large wall‑thickness variation of CA6NM duplex steel, the coating forms a uniform protective layer via two‑pass brushing process. After shot blasting, inner‑cavity burning‑on defects are eliminated, and post‑treatment cleaning workload is significantly reduced.
Ⅰ. Product Introduction of Alcohol‑Based Coating
AT‑100D alcohol‑based casting coating is a white‑paste coating designed for small‑to‑medium‑sized cast steel parts. Using alcohol as carrier solvent, it features self‑drying by ignition and shortens core drying cycle.
| Appearance | Suspension | Density | Baume Degree Be° |
|---|---|---|---|
| White paste | ≥98% | 1.8‑2.1 g/ml | ≥120 |
With excellent suspension, thixotropy and leveling performance, the coating delivers uniform film thickness after brushing and avoids coating accumulation and sagging. It is suitable for small‑to‑medium‑sized castings of stainless steel and carbon steel, and compatible with multiple molding systems including water‑glass sand, alkaline phenolic resin sand and phenolic‑urethane binder.
Ⅱ. Case Background: Burning‑On Defects of Duplex‑Steel Impeller
The validated casting is a double‑deck closed impeller made of CA6NM duplex steel. Process parameters are listed below:
| Material | Pouring Weight | Finished Casting Weight | Pouring Temperature | Pouring Time | Minimum Wall Thickness | Maximum Wall Thickness | Melting Equipment | Mold Type | Core Type |
|---|---|---|---|---|---|---|---|---|---|
| CA6NM | 130 kg | 90 kg | 1610 ℃ | 20‑25 s | 5 mm | 35 mm | Medium‑frequency Induction Furnace | Alkaline Phenolic Resin Sand | Coated Ceramsite Sand |
This impeller has sharp wall‑thickness difference ranging from 5 mm to 35 mm. Under pouring temperature up to 1610 ℃, high‑temperature molten steel brings severe erosion to molds and cores. In original production, external and inner‑cavity burning‑on occurred frequently. Inner‑cavity burning‑on was difficult and time‑consuming to clean, which became a major bottleneck restricting production efficiency.
Ⅲ. On‑Site Application Process
According to casting structure and material characteristics, two‑pass brushing was adopted.
| Procedure | Baume Degree | Remarks |
|---|---|---|
| 1st Brushing | 65 Be° | Primer layer for adhesion and basic thickness |
| 2nd Brushing | 60 Be° | Topcoat for surface smoothness and compactness |
Coating Performance:
‑ Total coating thickness: 0.25‑0.35 mm
‑ High surface strength
‑ Smooth surface, free of cracks and brush marks
Gradient Baume‑degree control with two‑pass brushing ensures full coverage on cores, and prevents cracking and accumulation caused by excessive single‑pass thickness.
Ⅳ. Field Application Results
Good Process Compatibility
For cast‑steel impellers with large wall‑thickness variation, uniform coating was obtained after core drying without accumulation or sagging. It matches composite molding system of alkaline phenolic resin sand mold and coated ceramsite sand core.
Superior High‑temperature Erosion Resistance
The protective coating isolates 1610 ℃ molten steel from direct contact with molds and cores. No obvious burning‑on was observed on outer surfaces after pouring and cooling.
Inner‑cavity Burning‑On Defect Eliminated
After shot blasting, inner‑cavity burning‑on defects were effectively solved and inner‑surface quality was greatly improved.
Reduced Post‑processing Cost
Cleaning workload for inner‑cavity burning‑on is largely cut down, grinding labor hours are reduced and casting delivery cycle is shortened.
High pouring temperature and wide wall‑thickness range make inner‑cavity burning‑on a typical frequent defect for CA6NM duplex‑steel impellers. By applying AT‑100D alcohol‑based casting coating together with standardized two‑pass brushing and gradient Baume‑degree control, dense, high‑strength and uniform protective coating is formed on cores. It resists erosion of high‑temperature molten steel and systematically improves burning‑on defects on both outer and inner surfaces.
This case verifies reliable performance of AT‑100D alcohol‑based coating on small‑to‑medium‑sized steel castings, especially stainless steel and duplex‑steel components with high pouring temperature. It provides a replicable solution for surface‑quality control of similar castings.
About Liaoning Xinda Foundry Technology Co., Ltd.: The company specializes in R&D and production of foundry materials. Its product portfolio covers furan resin, alkaline phenolic resin, various alcohol‑based coatings, water‑based coatings, ceramic foam filters, 3D‑printing‑specific resins, anti‑veining additives, exothermic risers and other products. We provide high‑performance materials and complete process solutions for global foundries.