Electroslag Remelting Technology

Electroslag remelting (ESR) is a widely used remelting process for the production of high-quality steels. Originally, this process was mainly used for deoxidation and desulfurization, in addition to controlling the solidification process, which significantly improved the distribution characteristics of non-metallic inclusions.

The main advantages of ESR are as follows:

A. Refinement of grains:

Due to the strong cooling effect of the mold and water-cooled base plate, the grains in the molten steel cannot grow during the melting process, resulting in a fine and uniform distribution of grains within the steel ingot, which improves the internal microstructure.

B. Reduction of non-metallic impurities and inclusions in the steel:

During the remelting process, the metal droplets pass through a certain thickness of the slag layer. The specific surface area (surface area per unit weight) of the metal droplets is several hundred times larger than that of the bulk metal, which significantly increases the steel-slag interface area. This enhances the ability of the slag to absorb non-metallic impurities and inclusions in the metal. Meanwhile, the impurities in the steel are redistributed according to the distribution law as they pass through the slag layer, reducing the concentration of impurities in the steel melt, effectively cleansing the steel.

C. Improvement of the steel's hot workability:

After electroslag remelting, the steel ingot has a fine and uniform grain structure, a dense microstructure, and a smooth surface. Additionally, the reduction of impurities in the steel can significantly decrease the sources of stress concentration and cracks during the hot working process. This helps to avoid the formation of cracks during forging, thereby improving the yield rate of the steel.

D. Reduction of macro- and micro-segregation, and improvement of the distribution of carbides in tool steels and die steels:

The electroslag remelting process can effectively reduce the macro- and micro-segregation in the steel ingot, and also improve the distribution of carbides in special steels, such as tool steels and die steels.

In summary, the electroslag remelting process can effectively improve the internal quality and surface quality of steel ingots, and is a widely used high-end steelmaking process.

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