Silicon manganese is an alloy composed of manganese, silicon, iron, and a small amount of carbon and other elements. Silicon manganese alloy is a composite deoxidizer commonly used in steelmaking, and silicon-manganese alloy can be smelted by continuous operation in large, medium, and small submerged arc furnaces.
Classification of Silicon Manganese
Silicon manganese can be divided into 8 grades according to the content of manganese, silicon, and their impurities. The following chart lists the silicon manganese analysis for chemical composition.
| Silico manganese code | Chemical composition(%) | ||||||
|---|---|---|---|---|---|---|---|
| Si | Mn | C | P | P | P | S | |
| Ι | Ⅱ | Ⅲ | |||||
| ≤ | ≤ | ≤ | ≤ | ≤ | |||
| FeMn64Si27 | 25.0-28.0 | 60.0-67.0 | 0.5 | 0.10 | 0.15 | 0.25 | 0.04 |
| FeMn67Si23 | 22.0-25.0 | 63.0-70.0 | 0.7 | 0.10 | 0.15 | 0.25 | 0.04 |
| FeMn68Si22 | 20.0-23.0 | 65.0-72.0 | 1.2 | 0.10 | 0.15 | 0.25 | 0.04 |
| FeMn64Si23 | 20.0-25.0 | 60.0-67.0 | 1.2 | 0.10 | 0.15 | 0.25 | 0.04 |
| FeMn68Si18 | 17.0-20.0 | 65.0-72.0 | 1.8 | 0.10 | 0.15 | 0.25 | 0.04 |
| FeMn64Si18 | 17.0-20.0 | 60.0-67.0 | 1.8 | 0.10 | 0.15 | 0.25 | 0.04 |
| FeMn68Si16 | 14.0-17.0 | 65.0-72.0 | 2.5 | 0.10 | 0.15 | 0.25 | 0.04 |
| FeMn64Si16 | 14.0-17.0 | 60.0-67.0 | 2.5 | 0.20 | 0.20 | 0.30 | 0.05 |
Main Uses of Silicon Manganese
Silicon manganese is mainly used as a deoxidizer and alloying agent in steelmaking to eliminate excess oxygen and sulfur in molten steel and improve the quality and performance of steel. Silicon manganese alloys are used as deoxidizers. In steelmaking, methods such as oxygen blowing are used to decarburize molten iron and remove harmful impurities such as phosphorus and sulfur. This process will increase the oxygen content in molten steel. Too high oxygen content will reduce the mechanical properties of steel. Add some elements that have a stronger binding force with oxygen than iron, and whose oxides are easy to be discharged from the molten steel in the form of slag to remove the oxygen in the molten steel. This process is called deoxidation.
Silicon and manganese in silicon-manganese alloy have a strong affinity with oxygen. When the silicon-manganese alloy is used in steelmaking, the resulting deoxidation products MnSiO3 and MnSiO4 melt at 1270°C and 1327°C respectively, with a low melting point, large particles, and easy to float. , good deoxidation effect, and so on.
Silicon can significantly improve the elasticity and magnetic permeability of steel, so when smelting structural steel, tool steel, spring steel, and silicon steel for transformers, silicon-based alloys must be used.
General steel contains 0.15%-0.35% silicon, structural steel contains 0.40%-1.75% silicon, tool steel contains 0.30%-1.80% silicon, spring steel contains 0.40%-2.80% silicon, stainless acid-resistant steel contains 0.40%-2.80% silicon. Stainless acid-resistant steel contains 3.40%-4.00% silicon, heat-resistant steel contains 1.00%-3.00% silicon, and silicon steel contains 2%-3% or higher.
Manganese can reduce the brittleness of steel, improve the hot workability of steel, and increase the strength, hardness, and wear resistance of steel. “Without manganese, no steel will be made”, manganese consumed by the steel industry accounts for more than 90% of its output. Manganese is an indispensable functional basic raw material for the production of high-quality steel. It can remove impurities such as sulfur and oxygen during the steelmaking process, and improve the physical properties of steel by improving strength, hardness, and wear resistance.