Rare earth ferro silicon magnesium alloy (RE-FeSiMg) is a highly efficient spheroidizing agent optimized by adding light rare earth elements (such as cerium and lanthanum) to ordinary magnesium silicon ferro alloys. It is widely used in the production of ductile iron, vermicular graphite cast iron, and high-quality cast steel.

The unique role of rare earth elements:

Compared with ordinary spheroidizing agents, the addition of rare earth elements brings three core advantages:

Resisting spheroidization fading: Rare earth elements can significantly extend the effective spheroidization time, making it particularly suitable for producing thick-section ductile iron castings (such as wind turbine hubs and large molds), preventing graphite distortion in the core.

Purifying molten iron: Rare earth elements have a strong affinity for harmful elements such as oxygen and sulfur in molten iron, playing a role in assisting desulfurization and deoxidation, further purifying the molten iron and improving the overall performance of the castings.

Improving graphite morphology: Rare earth elements can make graphite spheres more rounded, smaller, and more evenly distributed, thereby improving the strength, elongation, and impact toughness of ductile iron.

FeSiMg-11

Chemical composition

Grade	Chemical composition							Size	Application Scenarios and Key Roles
	Mg	Re	Si	Ca	Al ≤	Ti ≤	Fe
FeSiMg6RE2	5.5-6.5	1.5-2.5	40-44	2.0-3.0	0.5	0.5	margin	5-15mm / 8-25mm	Ordinary ductile iron parts: Suitable for small and medium-sized parts, high cost-effectiveness, and stable spheroidization ability.
FeSiMg7RE3	6.5-7.5	2.5-3.5	40-44	2.5-3.5	0.5	1.0	margin	5-25mm / 8-30mm	High-strength ductile iron: Such as crankshafts and connecting rods, requiring high strength and fatigue resistance.
FeSiMg8RE5	7.5-8.5	4.5-5.5	38-42	2.5-3.5	0.5	1.0	margin	8-30mm / 15-40mm	Thick-section ductile iron: Such as wind turbine castings and large molds, strong resistance to fading, ensuring core spheroidization rate.
FeSiMg8RE7	7.5-8.5	6.5-7.5	38-42	2.0-3.0	0.5	1.0	margin	15-40mm	Extra-thick, large-section/high-performance ductile iron: Ultra-high rare earth content, used to resist extreme cross-sectional sensitivity.
FeSiMg9RE5	8.5-9.5	4.5-5.5	38-42	2.5-3.5	0.5	1.0	margin	5-20mm	High-sulfur raw iron or special processes: High magnesium content compensates for burn-off, ensuring spheroidization effect.

Size customization:

Pumping method: 5-25mm or 8-30mm particles are recommended to ensure stable reaction and high absorption rate.

Thread feeding method: 0.5-2mm powder is recommended, requiring good flowability and narrow particle size distribution.

Covering method: 3-15mm particles are recommended, balancing reaction speed and yield.

Application areas

Steel smelting:

used for deoxidation and alloying in steel production such as converters and electric furnaces, especially in the production of high-performance steel.

Foundry industry:

used for casting steel and special steel to improve the quality and performance of casting products.

Special steel production:

suitable for the production of steel grades with special requirements for alloy composition, such as high-strength steel, wear-resistant steel and stainless steel.

FeSiMg alloy

FAQ

Q1: What is the difference between rare earth FeSiMg alloy and ordinary magnesium silicon ferro alloy (without rare earth elements)?

A1: The core difference lies in the resistance to fading and the purification effect on molten iron.

Ordinary MgSiFe alloy: Suitable for general small and medium-sized ductile iron parts, with lower cost.

Rare earth ferro magnesium silicon alloy: Contains rare earth elements (such as Ce and La). Rare earth elements can:

Extend the effective spheroidizing time, especially suitable for thick and large-section castings.

Combine with trace harmful elements such as oxygen, sulfur, lead, and bismuth in molten iron, playing a purifying role and improving the toughness and fatigue performance of ductile iron.

Make graphite spheres rounder and smaller.

If your product is a wind power casting, a critical automotive safety component, or has stringent performance requirements, we strongly recommend using rare earth magnesium-silicon ferroalloy.

Q2: What are the consequences if the spheroidizing agent gets damp? Can it still be used?

A2: Absolutely do not use damp spheroidizing agents! Magnesium in the spheroidizing agent is highly reactive; when exposed to moisture, it reacts with water to form magnesium hydroxide and release hydrogen gas. This leads to:

A sharp decrease in effective magnesium content, resulting in spheroidization failure.

The hydrogen gas produced is absorbed by the molten iron, forming casting defects such as porosity and white cast iron.

The reaction can be extremely vigorous during processing, potentially causing splashing and injury.

Please ensure it is stored in a dry, well-ventilated warehouse. It is best to bake it at a low temperature of 100-150℃ before use.

Q3: How to determine the effectiveness of spheroidization treatment?

A3: On the production site, a preliminary judgment can be made by quickly observing the fracture surface of a triangular test piece:

Good spheroidization: The fracture surface is silvery-gray, with fine and uniform grains, obvious shrinkage porosity in the center, and a tough sound similar to steel when struck.

Deteriorated spheroidization/non-spheroidization: The fracture surface is dark gray or black, with coarse grains, little or no shrinkage porosity in the center, and a crisp sound when struck.

Final confirmation still requires metallographic microscopy to test the graphite spheroidization rate.

Q4: What is your minimum order quantity (MOQ)? Can you provide samples for testing?

A4: As the source factory, we support foundries in conducting small-batch verification. The MOQ for standard grades is usually one container. We are also happy to provide 1-5 kg of free samples for you to test composition, size, and spheroidization effects in your laboratory or small furnace.

rare earth ferro silicon magnesium