The working principle and characteristics of electroslag remelting furnace (ESR)

Electroslag remelting is a method of smelting by using the resistance heat generated by the current passing through the slag as the heat source,The main purpose is to purify the metal and obtain uniform and dense ingot.The electroslag remelting steel has high purity, low sulfur content, less non-metallic inclusions, smooth surface, clean, uniform and dense steel ingot, uniform microstructure and chemical composition.

From the principle of heating, electroslag remelting furnace is a kind of resistance smelting furnace. Electroslag remelting process is  the lower end of the electrode is immersed in the molten slag.Alternating current passes through a high resistance slag bath to produce a large amount of heat. It melts the electrode end which is  immersed in molten slag,Molten metal droplets drop through the slag bath into the metal bath and then cooled into a ingot by cooling the mold,In this process, the metal droplet is fully contacted with the slag with high temperature and high basicity, which produces strong metallurgical reaction and makes the metal refined

VACUUM SLAG REMELTING FURNACEThe key technology of electroslag remelting furnace is slag system,In electroslag remelting furnace, the main function of slag has four points, namely 1:heat source action,2: protective action, 3:molding action 4:metallurgical chemical action.COOLDO believes that the chemical composition of slag has a great influence on the quality and technical and economic indexes of electroslag smelting products. The characteristics of slag are

1:(1) with high resistivity, enough heat can be produced during the melting process to ensure the melting, heating and purification of metals


2:it has a certain alkalinity, so its deoxidation and desulfurization effect is good

3:without stable oxides, such as MnO, FeO, etc..

  • good fluidity, so as to ensure the convection heat exchange and liquid physical and chemical reaction under high temperature.

having a lower melting point, generally lower than the melting point of the molten metal with 150-250 degrees, which makes the spindle form well

  • it has a high boiling point so that it can not volatilize in high temperature.
  1. Electric equipment of electroslag remelting furnace

In addition to the electric furnace transformer, there are 3 parts of the electric equipment in the electroslag remelting furnace

(1) high voltage side equipments are isolated switch, high voltage circuit breaker, high voltage transformer, high voltage current transformer and so on.

  • low voltage side equipment are: busbar busbar, low-voltage current transformer etc..
  • control equipment, including regulator cabinet, operating table, transmission motor, etc.

Figure 2 shows the main circuit diagram of double column electroslag furnace. Cooldo believes that compared with the single column type furnace busbar is arranged in parallel, it makes the offset, high power factor and reactance.

Compared with other remelting equipments, the main advantage of electroslag remelting furnace is that it is the main advantage of electroslag remelting furnace:

  • there is a strong metallurgical reaction between molten metal and slag, so the effect of phosphorus removal and sulfur removal is better, and the purity of spindle is relatively high.
  • the equipment is simple, high productivity and low investment.

(3) the molten slag can be separated from the outside air by molten metal and free from external pollution

(4) molten slag and molten metals produce metallurgical chemical reactions that can produce high-grade metals and alloys.

5) non-metallic inclusions in molten metal react with slag, and then non-metallic inclusions are removed by slag.

6) the spindle is cooled in a water-cooled copper crucible, the cooling speed is very fast, which leads to the internal structure of the spindle is uniform, no segregation.

The scope of application of ESR furnace is very wide, not only can be used in the production of air bearing steel, high temperature alloy, precision alloy and other non-ferrous metals, can also be used to produce hundreds of tons of large high-quality alloy steel ingot, large flat ingot or slab ingot, hollow ingot, composite plate, and casting rolls, gear blanks, turbine disc, pressure vessel, aircraft landing gear, barrel shaped castings etc.