How to choose a GPC recarburizer (carbon raiser)
Updated 2026-11-12
Choose a GPC recarburizer (also called carbon raiser, carbon additive or carburizer) by fixing four numbers on the purchase order: minimum fixed carbon, maximum sulfur, nitrogen target or ceiling, and particle-size range. Jiushun publishes grades ZW01–ZW04 with sulfur ≤0.05% and nitrogen 100–300 ppm by grade.
Start with the melt, not the brochure
Foundry and steel buyers usually care about recovery in the bath, sulfur pick-up, nitrogen for ductile iron, and how the carbon dissolves at the chosen size. Ask the melt shop which of those four constraints is hard.
Read a grade table before you ask for a price
| Decision | What to write on the enquiry |
|---|---|
| Fixed carbon | Minimum % required for the heat |
| Sulfur / sulphur | Maximum % the melt can accept |
| Nitrogen | Ceiling in ppm if ductile iron is sensitive |
| Size | mm range (1–5 mm is most requested overseas) |
| Quantity | Tonnes and packing preference |
Jiushun sheet grades
| Grade | F.C. min | S max | Ash max | V.M. max | Moisture max | N |
|---|---|---|---|---|---|---|
| ZW01 | ≥99.0% | ≤0.05% | ≤0.5% | ≤0.5% | ≤0.50% | 100 ppm |
| ZW02 | ≥98.5% | ≤0.05% | ≤0.6% | ≤0.9% | ≤0.50% | 200 ppm |
| ZW03 | ≥98.5% | ≤0.05% | ≤0.7% | ≤0.8% | ≤0.50% | 200 ppm |
| ZW04 | ≥98.0% | ≤0.05% | ≤1.0% | ≤1.0% | ≤0.50% | 300 ppm |
Source: factory specification sheet. Indicators and particle sizes can be customised to the purchase order.
ZW01 lists the highest fixed carbon and the lowest nitrogen figure on the sheet. ZW04 is the entry grade. Indicators and sizes can still be customised when the sheet grades do not fit.
What not to ask the website for
This site does not publish prices, capacity or container tonnage. Send company, country, grade, size and quantity to contact.