FSMg cast iron, Dnepropetrovsk region.

"
The FSMg9 brand is used for ladle modification in the production of large mass castings.

The FSMg7, FSMg5 brands are the most widely used for in-form modification in the production of high-strength cast iron castings.
(//tractor-service.com)
Low-magnesium grades FSMg4, FSMg3 are used for preliminary modification in a ladle, or when modifying pure sulfur (0.005-0.01%) cast iron.

The presence of calcium in the modifiers makes it possible to control the speed of their dissolution, contributes to the refining of cast iron from sulfur and oxygen, however, the content of calcium is limited, since at values of more than 5%, the modifier is slagging and poorly absorbed by the melt.Additives RZM (rare earth metals) contribute to changing the shape of graphite globules, their grinding, neutralization of deglobulizer elements (Bi, Sn, Sb, Pb) by forming stable intermetallics.

The brand of the modifier and the size class are selected taking into account the method of modification, the mass and cross-section of the castings, the chemical composition of the cast iron and the achievement of the specified properties in the castings.
"