What are the benefits of using ferro silicon 75 in steelmaking?

FerroSilicon 75 is a binary ferrosilicon alloy with a silicon content of 72%-80% and an iron content of 25%-29%. Its impurity content conforms to GB/T 2272-2017 standard (Al≤1.0%, S≤0.05%, P≤0.04%). Its core characteristics support its suitability for steelmaking:

 Melting point approximately 1280℃, rapid dissolution in molten steel (complete dissolution in 5-8 minutes), and high reaction efficiency;
 Low free energy of reaction between silicon and oxygen, strong deoxidizing activity, and easily separated products;
 Good compositional stability (silicon content fluctuation ≤±2%), allowing for precise matching of alloying requirements for different steel grades.

(1) High-efficiency deoxidation: Improving the purity of molten steel and reducing defects

FeSi75% optimizes the quality of molten steel from the root through a dual action of "precipitation deoxidation + slag collection and purification":

Deoxidation mechanism:

Silicon undergoes a displacement reaction with FeO in the molten steel (Si + 2FeO → SiO₂ + 2Fe). The generated SiO₂ has a density of only 2.65 g/cm³, far lower than that of the molten steel, and will quickly float to the slag and be removed; at the same time, SiO₂ can form low-melting-point composite slag (melting point around 1400℃) with CaO and Al₂O₃, enhancing the slag's ability to adsorb inclusions.

Quantitative Effect:

When the addition amount is 0.3%-0.8% of the steel mass, the oxygen content of the steel can be reduced from 80-100ppm to 30-50ppm, and the deoxidation efficiency is 30% higher than that of traditional ferrosilicon (such as FeSi65).

Process Adaptability:

In converter steelmaking, it can be used as a pre-deoxidizer (added before tapping) or a final deoxidizer (added during tapping). In LF furnace refining, it can be used for deep deoxidation, adapting to the needs of different smelting stages.

(2) Precise Alloying: Customizing the Mechanical and Functional Properties of Steel

FerroSilicon 75% achieves precise optimization of steel properties through solid solution strengthening and composition control, adapting to the needs of different industries:

Strengthening Mechanism:

After silicon atoms dissolve in the ferrite lattice, they induce lattice distortion, hindering dislocation movement, and simultaneously refining the grains (grain size reduced from 50μm to 30-40μm), significantly improving the strength and hardness of the steel. Application Effects of Different Steel Grades:

Structural Steel (e.g., Q355):

Adding FeSi75 controls the silicon content in the steel to 0.2%-0.5%, increasing tensile strength by 10%-12% without reducing toughness (elongation ≥21%), suitable for engineering structural components;

Tool Steel:

Silicon content controlled at 0.30%-1.8%, hardness increased to HRC55 or higher, wear resistance enhanced by 30%-40%, suitable for cutting tool and mold production;

Spring Steel:

Silicon content 0.40%-2.8%, elastic limit increased by 20%-25%, fatigue life extended by 1.5-2 times, meeting the high load requirements of automotive and mechanical springs;

Transformer Silicon Steel:

Silicon content 2.81%-4.8%, iron loss reduced by 20%-25%, magnetic permeability increased by 15%-20%, power transmission efficiency improved by 3%-5%.

(3) Cost Reduction and Efficiency Improvement: Optimizing Production Energy Consumption and Overall Cost

The cost-effectiveness advantage of 75# FeSi runs through the entire steelmaking process, achieving the dual goals of cost reduction and efficiency improvement:

Raw material cost savings:

The unit silicon cost is 8%-10% lower than FeSi90 and 15%-20% lower than FeMn alloy;

Energy consumption optimization:

Due to its low melting point and fast dissolution, smelting time can be shortened by 10%-15%, reducing the electricity consumption per ton of steel in electric arc furnace steelmaking by 8%-12% (approximately 60-80 kWh/ton of steel), and reducing oxygen consumption by 3%-5% in converter steelmaking;

Auxiliary material savings:

The SiO₂ generated during deoxidation can be used as a core component of slag, reducing the amount of slag-forming agents such as lime by 15%-20%, and reducing the cost of auxiliary materials per ton of steel by 8-12 yuan.

(4) Process Stability: Enhancing the Compatibility of Smelting and Casting

Ferro Silicon 75% optimizes the physical properties of molten steel, ensuring smooth production processes and reducing defect rates:

Improving molten steel fluidity:

Reducing surface tension and viscosity by 15%-20%, making it easier for molten steel to fill the mold, reducing casting defects such as "insufficient pouring" and "cold shut," and increasing ingot recovery rate by 2%-3%;

Stabilizing the smelting process:

Alleviating problems such as molten steel splashing and slag overflow, increasing the endpoint hit rate of converter blowing by 10%-15%, reducing the number of reblowing cycles, and reducing compositional fluctuations during the smelting process;

Adapting to continuous casting:

Optimizing the solidification characteristics of molten steel, reducing the incidence of central porosity and segregation defects in continuously cast billets by 30%-40%, and improving the quality stability of subsequent rolled products.