Die steel production process: difference between electric furnace and electroslag
Careful customers often struggle to choose which material is more appropriate when choosing mold steel, because the price is comparable and the quality is better in the market response. In fact, when we choose, in addition to some basic elements, one point to pay attention to is whether the material belongs to electric furnace steel or electroslag steel, which is also the focus of this article.
Let's first understand the meaning of the two:
Electric furnace: refers to electric heating equipment to achieve the intended process purpose (such as smelting, melting, heating, heat treatment, sintering, drying, etc.).
Electroslag: Electroslag (melting casting) is a secondary refining technology, a comprehensive metallurgical casting process combining secondary refining of molten steel with directional solidification. The principle is that the current passes through the liquid slag pool to resist heat, melt the metal electrode, and the melted metal is gathered into a melt drop, which passes through the slag layer into the metal melt pool, and then crystallizes into steel ingot in the water-cooled crystallizer.
From the above two meanings, we basically understand that electroslag is the second stage of the electric furnace process, in fact, a lot of steel is not electroslag treatment after the electric furnace process, which makes the steel has not been refined, and can not ensure the purity of steel.
The full name of electroslag steel is electroslag remelting steel, referred to as ESR, as the name suggests is the need to melt twice out of the ingot, this process is more complex than electric steel, the relative performance of steel is much better, including the purity of steel.
An important advantage of electroslag steel is that non-metallic inclusions in steel are absorbed by slag, which is also a feature that electric furnace steel does not have. The harmful elements (sulfur, lead, antimony, bismuth, tin) in steel are effectively removed by steel-slag reaction and high-temperature gasification.
At the same time, the liquid metal is covered by the slag pool, which basically avoids reoxidation. Because it is melted, refined and solidified in the copper water-cooled crystallizer, it eliminates the pollution of the refractory material to the steel. Before the ingot solidified, there is a metal melting pool and slag pool at the upper end of the ingot, which plays the role of heat preservation and feeding to ensure the densification of the ingot. The rising slag pool forms a thin slag shell on the inner wall of the mold, which not only makes the surface of the ingot smooth, but also plays an insulating and heat insulation role, so that more heat is conducted to the lower part, which is conducive to the oriented crystallization of the ingot from the bottom up.
In summary, the quality and performance of steel ingot produced by electroslag remelting are improved, the plasticity and impact toughness of alloy steel at low temperature, room temperature and high temperature are enhanced, and the service life of steel is extended.
