For added steel smelting of sulfur to improve machinability, bred effects and graphite morphology to improve the mechanicla properties of gray cast iron.
Please find the specification as follow.
FeS30: S:28-35 C:0.20 Si:7.0 Mn:0.20 P:0.20 As:0.05 Fe:50
FeS40: S:35-45 C:0.30 Si:5.0 Mn:0.20 P:0.25 As:0.15 Fe:40
FeS50: S:45-55 C:0.30 Si:3.0 Mn:0.20 P:0.25 As:0.10 Fe:40