What sulfur and nitrogen levels mean for ductile iron

On the Jiushun factory sheet, all ZW grades list sulfur ≤0.05% (low sulfur / low sulphur). Nitrogen is listed as 100 ppm (ZW01), 200 ppm (ZW02/ZW03) and 300 ppm (ZW04). Ductile-iron buyers who need a nitrogen ceiling should write that ceiling on the purchase order and COA — not rely on a grade nickname alone.

Sulfur

Sulfur in the recarburizer / carbon additive adds to the melt sulfur balance. Low-sulfur GPC is often preferred when the shop already fights sulfur from other charge materials. Jiushun’s published ZW grades share the same sulfur maximum: ≤0.05%.

Nitrogen

Nitrogen sensitivity varies by process and final iron grade. The sheet values above are the factory’s listed figures for ZW01–ZW04. If your metallurgy needs a stricter ceiling (for example below the listed grade figure), state it as a contractual maximum before production.

How to enquire with high intent

Use the contact form and fill the optional nitrogen ceiling field together with grade, particle size and quantity. That is enough for sales to match a sheet grade or propose a custom indicator set. See also ductile iron.