Ferrophosphorus is added to steel to improve strength and machinability. It is added to grey iron to increase fluidity. Ferrophosphorus is generally added to the ladle after the steel has been thoroughly deoxidized. The addition of ferrophosphorus in some alloys can improve corrosion resistance.

Chemical Analysis: 20-25% Mn: 4% max, Si: 3% max, S: 0.01% max, C: 0.05% max