Dr E. Ramanathan PhD
Typical Degreasing Concentrate Formula
Used prior to trication phosphating to ensure optimal surface preparation.
1. Alkaline Degreasing Concentrate Formula (by weight %)
For oily steel surfaces; suitable for spray or dip.
| Ingredient | % w/w |
|---|---|
| Sodium metasilicate (5H₂O) | 25.0 |
| Sodium carbonate (soda ash) | 20.0 |
| Sodium hydroxide (flakes) | 10.0 |
| Non-ionic surfactant (e.g., NP-10) | 5.0 |
| EDTA (optional, for hardness control) | 1.0 |
| Sodium gluconate (optional chelator) | 2.0 |
| Water (to make 100%) | 37.0 |
Use dilution: 3–5% in water
Operating temp: 50–70°C
pH: >11
2. Derusting / Pickling Concentrate Formula (Mild Acid Type)
For removal of rust/mill scale after degreasing.
| Ingredient | % w/w |
|---|---|
| Phosphoric acid (85%) | 50.0 |
| Non-ionic surfactant | 1.0 |
| Thiourea (acid inhibitor) | 0.5 |
| Benzotriazole (flash rust inhibitor) | 0.5 |
| Water | 48.0 |
Use dilution: 10–20% in water
Operating temp: ambient to 50°C
Contact time: 3–10 minutes
Notes:
- For heavy-duty degreasing, increase NaOH and use a stronger emulsifier.
- For derusting, inhibit strongly if steel is to be exposed after treatment.
- Always rinse thoroughly after both degreasing and pickling to remove residues.
