Ferroalloys are alloy materials based on iron, combined with one or more metallic/non-metallic elements (such as silicon, manganese, chromium, vanadium, titanium, etc.). They are not directly used to manufacture end products, but serve as "additives" and "modifiers" in steel production.

In terms of composition, the core characteristics of ferroalloys are:

  • Iron content is usually 40%-90%, with the rest being alloying elements (iron content in some high-purity ferroalloys can be less than 30%);
  • Alloying elements exist in the form of "solid solutions" or "intermetallic compounds", featuring high stability and excellent physical and chemical properties;
  • Melting points are generally higher than pure iron (1538℃), and some high-temperature ferroalloys have melting points exceeding 1800℃, which can adapt to the high-temperature environment of steel smelting.
The ferroalloy family is extensive. According to the main alloying elements, it can be divided into several categories of core members, each with unique "skills":

Ferro silicon

Represented by ferrosilicon (Fe-Si), with a silicon content usually between 10%-90%, it is the most widely used ferroalloy in steel production.

Core function: Silicon has a strong affinity for oxygen. During steelmaking, it can quickly "capture" oxygen in the molten steel, avoiding defects such as pores and inclusions in steel, while improving the hardness and electrical conductivity of steel;

Common applications: Deoxidation of ordinary carbon steel and low-alloy steel; raw material for silicon steel (electrical steel) used in transformer cores (high silicon content can improve magnetic permeability and reduce power loss).

Including ferromanganese (Fe-Mn), ferromanganese-silicon (Fe-Mn-Si), etc., with a manganese content ranging from 60%-95%, it is the key to improving steel strength.

Ferro manganese

Ferromanganese is an iron alloy composed of manganese and iron, which is classified into several types, including high-carbon ferromanganese (containing 7% to 8% carbon), medium-carbon ferromanganese (containing 1.0% to 1.5% carbon), low-carbon ferromanganese (containing 0.2% to 0.7% carbon), micro-carbon ferromanganese (containing 0.05% to 0.15% carbon), metallic manganese, mirror iron, and silicon-manganese alloy.

Ferromanganese is mainly used in steelmaking as a deoxidizer, desulfurizer and alloy additive. When added as an alloying agent to steel, it can improve the mechanical properties of steel, increase its strength, ductility, toughness and wear resistance. High-carbon ferromanganese can also be used in the production of medium and low-carbon ferromanganese.

Centered on ferrochromium (Fe-Cr), with a chromium content usually between 50%-75%, it is the "soul raw material" of stainless steel.

Ferro chromium

Core function: Chromium can form a dense chromium oxide film on the steel surface, preventing internal metal from corrosion and improving high-temperature strength;

Common applications: 304, 316 and other series of stainless steel (tableware, kitchenware, chemical equipment), superalloys (aeroengine blades).

This type of ferroalloy contains rare elements such as vanadium, titanium, niobium, and molybdenum. Although used in small amounts, they have "strong effects" and are the "finishing touch" for high-end steel:

Ferro Vandium

Ferrovandium (Fe-V): Improves the strength, toughness and corrosion resistance of steel; used in high-speed rail rail steel and high-strength steel for bridges;

Ferrotitanium

Ferro titanium (Fe-Ti): Refines grains and purifies molten steel; used in ultra-high strength steel for aerospace and marine engineering equipment steel;

Ferro molybdenum

Ferromolybdenum (Fe-Mo): Enhances the high-temperature stability and wear resistance of steel; used in steam turbine blades and oil drill pipes.