Ferro Silicon Magnesium ( FeSiMg )

Ferro silicon magnesium, also known as FeSiMg alloy, is a remelting alloy made up of Ferro silicon, Magnesium, rare earth, and Calcium.
As an additive, it can crystallize the graphite in cast iron into a ball shape. Its’ main elements are Si, Mg, Re, Ca, etc. The silicon magnesium alloys containing rare earth elements are divided into ordinary rare earth nodularizer and yttrium base heavy rare earth nodularizer. 

FeSiMg Composition

ferro silicon magnesium composition
fesimg composition

Si:43%-48% ,


Total rare earths:0.8–1.2%,



size:5-25 mm

Ferro Silicon Magnesium is a kind of good nodulizer, sometimes it also contains Rare Earth element, with strong mechanical strength, the effect of deoxidization and desulfurization is strong. It’s widely used in the metallurgic industry. It is one of the most important additives in the production process of spheroidal graphite iron.

The invention of ferro silicon magnesium is one of the most important milestone in nodular cast iron production history. It helps graphitization of the cast iron. Spheroidized graphite will make its strength far better than gray cast iron, meanwhile its toughness better than malleable cast iron, and keep other properties same with gray pig iron at the same time. Those advantages come from several nodulizing elements including Mg, Ce, Ca etc.  

Started from Cerium nodulizer at earliest time,but then people realized that Cerium is very hard to obtain, and it has strict requirement to melted steel. Then Mg spheroidizing agent was found, and evolved from Mg-Ni Alloy, Mg-Cu Alloy, and finally to FeSiMg Alloy Nodulizer.  Ferro Silicon Magnesium is easy for mass production, and as nodulizing agent, it expanded the production of Ductile Iron.

ferro silicon magnesium manufacturer

Ferro Silicon Magnesium Uses

★ Deoxidizer for steelmaking.
★ Inoculant and Nodulizer for cast iron.
★ Alloying agent.

Application :
Nodulisation is a process of controlling the structure and properties by changing the graphite shape from flakes to spheroidal in cast iron during solidification. A noduliser is a material which contains spheroidal graphite forming elements such as Mg, Ce, Ca, Ba, etc.
ZHENXIN supplies FeSiMg containing Ce which acts as a combination of these elements. A certain quantity of Magnesium in solution in the base metal is necessary to obtain the graphite is spheroidal form. On the other hand silicon which is the primary graphitising element prevents carbide formation and controls the release of Mg.
ZHENXIN has two types of nodulisers which is used in foundry for the production of nodular cast iron (Ductile Iron)
FeSiMg(5.0-5.50;5.50-6.00 and 9.5-10.0 Mg content)

FeSiMg uses
ferro silicon magnesium fesimg

This Ferro Silicon Magnesium alloy is used by almost every steel and iron plant as an oxidizing agent for iron and steel. The combined properties of Silicon and Magnesium increase strength, ductility, rigidity and high resistance of the steel.

What is the Composition of Ferro Silicon Magnesium?

A magnesium ferrosilicon alloy for in-mold nodulization of ductile iron consisting of 5-15% by weight of magnesium, 60-80% silicon, 0.1-1.5% calcium, 0.1-3.0% aluminum, 0-2.5% rare earth, and balance iron.

Nodular Iron Production: FeSiMg is a crucial additive in the production of nodular or ductile iron, which is characterized by its enhanced ductility, toughness, and strength. The alloy contains a high percentage of magnesium (typically 4-6%) along with silicon and iron. When added to the molten iron, FeSiMg reacts with sulfur and oxygen impurities, resulting in the formation of magnesium oxide (MgO) and magnesium sulfide (MgS). These byproducts create favorable conditions for the formation of graphite nodules during solidification, preventing the formation of brittle flakes or lamellar graphite. The nodules in ductile iron improve its mechanical properties and make it more suitable for applications requiring high strength and ductility, such as automotive components, pipes, and machinery parts.

Improved Mechanical Properties: The addition of FeSiMg to iron helps control the microstructure and properties of the resulting alloy. The graphite nodules formed through the nodularization process provide ductility, reducing the brittleness associated with traditional gray iron. The nodules act as stress concentrators, preventing the propagation of cracks and enhancing the overall toughness and impact resistance of the material.

Heat and Wear Resistance: Nodular iron produced with FeSiMg exhibits good thermal conductivity and resistance to thermal fatigue. These properties make it suitable for applications involving high temperatures, such as engine components, exhaust manifolds, and industrial machinery. Additionally, nodular iron has good wear resistance, making it suitable for parts subjected to abrasion or sliding contact, like gears, camshafts, and rollers.

Machinability: Nodular iron produced with FeSiMg has improved machinability compared to other iron alloys. The graphite nodules act as internal lubricants during machining operations, reducing tool wear and improving surface finish.

Cost Efficiency: FeSiMg is a cost-effective alloy, as it provides the desired nodularization effect while using relatively smaller amounts of magnesium compared to other alloys. This contributes to its widespread use in the production of ductile iron.

Overall, ferro silicon magnesium plays a critical role in the production of nodular iron, offering superior mechanical properties, heat resistance, wear resistance, machinability, and cost efficiency.

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