[SMM Science Popularization] SiMn Alloy: The "Invisible Guardian" of the Steel Industry

1. Production Process of SiMn Alloy:

First, raw materials such as manganese ore, manganese-rich slag, sinter, coke, silica, dolomite, and fluorite are mixed during the batching stage.

Next, the mixture undergoes smelting in an electric furnace, requiring both water and electricity supply. The smelted product is separated using a slag-iron separator, with the separated slag being quenched with water and then sent to a slag pond.

Subsequently, after sand molding and sampling, the samples are sent for quality inspection in the laboratory. Products that pass the inspection are crushed and then either directly stored in warehouses or transported as finished products for final sale.

The entire process reflects the transformation of manganese-silicon production from raw materials to finished products, involving multiple stages including batching, smelting, separation, inspection, and storage. Each stage significantly impacts the quality of the final product.

2. Major Domestic Production Regions of SiMn Alloy: Currently, Inner Mongolia, Ningxia, Guangxi, and Guizhou are the four major production regions for SiMn alloy in China, accounting for over 70% of the country's total SiMn production capacity and output. Among them, Inner Mongolia's SiMn production accounts for approximately 42% of the country's overall SiMn output. Inner Mongolia is currently the largest SiMn production region in China, with most manufacturers concentrated in the Ulanqab area. Large and medium-sized SiMn enterprises account for about 60% of the entire region.

3. Classification of SiMn Alloy Models:

Common models of SiMn alloy include FeMn68Si18 (6517), FeMn64Si14, and FeMn60Si28, with FeMn68Si18 (6517) being the main model under China's current standards.

①. FeMn68Si18 (6517): This is the current standard model in China, with a manganese content of 65%-72% and a silicon content of 17%-20%. It is widely used in steel smelting due to its stable chemical composition and excellent deoxidizing properties.

②. FeMn64Si14: This model has a slightly lower manganese content (approximately 64%) and a silicon content of 14%, suitable for specific smelting requirements.

③. FeMn60Si28: This is a high-silicon type (28% silicon) with a manganese content of 60%, often used in the production of special alloys.

4. Uses of SiMn Alloy:

SiMn alloy has a wide range of applications in steel production. It is an excellent deoxidizer and alloying agent that can remove deoxidizing elements from steel and adsorb them into the alloy, thereby improving the purity and quality of the steel. Meanwhile, the manganese in SiMn alloy can also enhance the tensile strength and wear resistance of steel, making it more durable.

①. Role as a Deoxidizer:

The silicon and manganese in SiMn alloy can combine with oxygen in steel to form stable oxides, thereby removing oxygen from the steel and improving its purity. This deoxidizer is more effective than ferrosilicon and pure silicon because the manganese in SiMn alloy can enhance the deoxidizing effect of silicon, making the deoxidation reaction more complete.

②. Alloying effect

SiMn alloy can be used as an alloy additive to improve the properties and strength of steel, thereby extending the service life of steel. Adding a certain amount of SiMn alloy to steel can increase its strength, hardness, wear resistance, tensile strength, yield point, and elongation, while also improving its corrosion resistance and high-temperature performance.

③. Cost reduction and efficiency improvement

SiMn alloy is a multifunctional material that can be used in the production of stainless steel, alloy steel, heat-resistant steel, spring steel, and other types of steel. Compared with ferrosilicon and pure silicon, SiMn alloy is more reasonably priced and can improve the efficiency of steel production and reduce costs after use.