Main Characteristics of Electric Arc Furnace

Main Characteristics of Electric Arc Furnace

Electric energy is the main energy source in electric arc furnaces. Electrical energy is produced by arc striking with graphite electrode and charge-discharge, which can produce high temperature over 2000 ~ 6000 C. The scrap steel material is melted by means of arc radiation, temperature convection, and heat conduction. For most of the time when the charge is melted, the high-temperature heat source is surrounded by the charge, so the heat loss caused by the high-temperature exhaust gas is relatively small, so the thermal efficiency is higher than other steelmaking equipment such as converter. In addition, electric heating can easily and accurately control the furnace temperature and can be operated under any conditions such as oxidation or reduction atmosphere, atmospheric pressure, or vacuum according to process requirements.

The process flow of electric arc furnace steelmaking is short, the equipment is simple, the operation is convenient, the pollution is easy to control, the construction investment is small and the area is small, so it does not need to rely on the complicated iron-making system like converter steelmaking.

Electric arc furnace steelmaking has strong adaptability to charge. It mainly uses scrap steel as raw material, but also can use solid and liquid ferrous materials such as hot water (hot metal for blast furnace or iron carbide), sponge iron (DRI), or hot-pressing block (HBI), pig iron, and so on.

Because the operation of a controllable atmosphere, slag adjustment or replacement in electric arc furnace is easy, and the complex process operations of melting, decarbonization, dephosphorization, degassing, inclusion removal, temperature control, composition adjustment (alloying), and other stages can be completed in the same operating system. The electric arc furnace steelmaking can be produced discontinuously and the production varieties can be changed flexibly within a certain range. In addition, modern electric arc furnaces can also use a lot of auxiliary energy, such as injecting heavy (light) oil, coal powder, natural gas, etc. Therefore, the electric arc furnace steelmaking process has strong adaptability, flexible operation, and wide application.

The electric arc furnace is not only capable of smelting high-quality steel with low content of phosphorus, sulfur, and oxygen but also can be alloyed with various elements (including oxidizable elements such as lead, boron, vanadium, titanium, and rare earth) to produce various high-quality steels and alloy steels, such as ball-bearing steel, stainless acid-resistant steel, tool steel, electrical steel, heat-resistant steel, magnetic material, and special alloys.

Although electric arc furnace steelmaking has many advantages, it is impossible to compete with converter steelmaking on Pudong Steel and long-term products due to the problems of waste steel and electricity price in China. Electric arc furnace steelmaking only plays a dominant role in the special steel production field with small-batch, multiple varieties, and high alloy ratios.

At present, some short-process electric furnace manufacturers in the world generally use electric arc furnaces with high output power. In addition, the traditional three-stage operation with reduction period has been gradually replaced by combined processes such as off-furnace refining, electric arc furnaces, and so on.

The equipment of public and auxiliary facilities is also more perfect and reasonable. The proportion of electric furnace steel output in the world is increasing year by year.

China is a developing country, capital construction has just begun, a large-scale scrap steel recovery period has not yet arrived, China's power development is not balanced, and the current electricity price is still in a relatively high stage. Therefore, the development speed of electric arc furnace steelmaking in China is limited, and no converter steelmaking develops rapidly. Although the total quantity of EAF steel is also increasing, the proportion of EAF steel output to total steel output decreases year by year, which is contrary to the development trend of EAF in the world.

Free send inquiries to stella@hanrm.com if any needs.

Email: stella@hanrm.com Or stellarollingmill@gmail.com

Whatsapp/Wechat:+8615877652925

Website:  https://www.hanrm.com

More News You May Interesting:

Energy Saving and Emission Reduction in Steelmaking Production

Alkaline EAF( Electric Arc Furnace) Oxidation Smelting Process

Nine Ways to Save Electricity in Steel-making Electric Furnace

Energy Efficiency Control System of Submerged Arc Furnace

EAF Steelmaking Cleaner Production Technology

What is Metallurgical Equipment?

Roller Hearth Reheating Furnace

Classification of Electric Arc Furnace

Furnace Transformer – Electric Arc Furnace

Melting Features of Medium Frequency Electric Furnace 

Electric Arc Furnace VS The Intermediate Frequency Furnace

The Function and Working Principle of Rolling Mill Heating Furnace

How Does Electric ARC Furnace Work?(B)

How Does Electric ARC Furnace Work?(A)

What are the Advantages and Disadvantages of Blast Furnace?

Characteristics of Electric Arc Furnace Steelmaking

Walking Beam Reheating Furnace VS Push-steel Reheating Furnace

Why Intermediate Frequency Furnace cannot be Turned on Normally?

The History of Electric Arc Furnace

How Does an Electric Arc Furnace Work?

How Does an Electric Arc Furnace Work?

The electric arc furnace is an electric furnace that uses the high temperature produced by the electrode arc to melt ores and metals. When gas discharge forms an arc, the energy is very concentrated and the temperature in the arc zone is above 3000 ℃. For smelting metal, the electric arc furnace is more flexible than other steelmaking furnaces and can effectively remove impurities such as sulfur and phosphorus. The furnace temperature is easy to control and the equipment covers a small area. It is suitable for smelting high-quality alloy steel. Arc furnaces can be divided into three-phase electric arc furnaces, consumable electric arc furnaces, single-phase electric arc furnaces, and resistance electric arc furnaces according to the arc form.

Electric arc furnace steelmaking uses graphite electrode to input electric energy into electric arc furnace, and takes arc between electrode end and charge as the heat source for steelmaking. Electric energy is used as the heat source in electric arc furnace, which can adjust the atmosphere in the furnace. It is very advantageous to melt steels containing more oxidizable elements. Shortly after the invention of electric arc furnace steelmaking, it was used to smelt alloy steel and gained great development.

With the improvement of electric arc furnace equipment and smelting technology, and the development of the electric power industry, the cost of electric arc furnace steelmaking is decreasing continuously. Now electric arc furnace steelmaking is not only used to produce alloy steel, but also to produce common carbon steel in large quantities. Its output proportion in the total output of steel in major industrial countries is increasing constantly.

Because it is difficult for the three-phase electrodes of the electric arc furnace to contact the uneven burden at the same time when heating the raw material, the combustion of the electric arc furnace is unstable, which causes an unbalanced three-phase load and generates harmonic current, which is injected into the power grid through the triangular connecting coil of the transformer. The main harmonics are 2-7 harmonics, with an average of 8% to 20% of fundamental waves and a maximum of 45%. The power quality of the power grid is seriously affected.

Free send inquiries to stella@hanrm.com if any needs.

Email: stella@hanrm.com Or stellarollingmill@gmail.com

Whatsapp/Wechat:+8615877652925

Website:  https://www.hanrm.com

More News You May Interesting:

Energy Saving and Emission Reduction in Steelmaking Production

Alkaline EAF( Electric Arc Furnace) Oxidation Smelting Process

Nine Ways to Save Electricity in Steel-making Electric Furnace

Energy Efficiency Control System of Submerged Arc Furnace

EAF Steelmaking Cleaner Production Technology

What is Metallurgical Equipment?

Roller Hearth Reheating Furnace

Classification of Electric Arc Furnace

Furnace Transformer – Electric Arc Furnace

Melting Features of Medium Frequency Electric Furnace 

Electric Arc Furnace VS The Intermediate Frequency Furnace

The Function and Working Principle of Rolling Mill Heating Furnace

How Does Electric ARC Furnace Work?(B)

How Does Electric ARC Furnace Work?(A)

What are the Advantages and Disadvantages of Blast Furnace?

Characteristics of Electric Arc Furnace Steelmaking

Walking Beam Reheating Furnace VS Push-steel Reheating Furnace

Why Intermediate Frequency Furnace cannot be Turned on Normally?

The History of Electric Arc Furnace

What is Submerged Arc Furnace?

What is Submerged Arc Furnace?

Submerged arc furnace is also known as an electric arc furnace or resistance furnace, also known as a reduction furnace or submerged arc furnace. One end of the electrode is embedded in the material layer to form an arc in the material layer and heat the material by using the resistance of the material layer itself; It is commonly used for smelting ferroalloy (see ferroalloy electric furnace), smelting ice nickel and matte (see nickel and copper), and producing calcium carbide (calcium carbide). It is mainly used for reducing smelting ore, carbonaceous reducing agents, solvents, and other raw materials. It mainly produces ferrosilicon, ferromanganese, ferrochromium, ferrotungsten, silicon manganese alloy， and other ferroalloys. It is an important industrial raw material in the metallurgical industry and chemical raw materials such as calcium carbide. It is characterized by using carbon or magnesium refractory as furnace lining and self-cultivation graphite electrode. The electrode is inserted into the charge for submerged arc operation. The energy and current of the arc are used to smelt the metal through the energy generated by the resistance of the charge. It is an industrial electric furnace with continuous feeding, intermittent iron slag discharge, and continuous operation. At the same time, the calcium carbide furnace and yellow phosphorus furnace can also be attributed to the submerged arc furnace due to the same use and working state, but due to the yellow phosphorus furnace. Pure resistive load, so there is also a saying that the yellow phosphorus furnace is attributed to the resistance furnace.

Equipment Composition:

Submerged arc furnace is an industrial electric furnace with huge power consumption. It is mainly composed of furnace shell, furnace cover, furnace lining, short net, water cooling system, smoke exhaust system, dust removal system, electrode shell, electrode pressure release and lifting system, loading and unloading system, controller, burn-through device, hydraulic system, submerged arc furnace transformer and various electrical equipment.

Type and Application of Submerged Arc Furnace

Category	Main raw materials	Manufactured products	Reflect temperature 0℃	Power consumption KW*h/t
Ferroalloy FerrosiliconFurnace (45%)Ferrosilicate	Scrap iron, coke, ferrosilicon	Ferrosilicon	1550-1770	2100-5500
Ferroalloy FerrosiliconFurnace (75%)Ferrosilicate	Scrap iron, coke, ferrosilicon	Ferrosilicon	1550-1770	8000-11000
Ferromanganese furnace	Manganese ore, waste iron, coke, lime	Ferromanganese	1500-1400	2400-4000
Ferro-chromium furnace	Chromium ore, silica, coke	Ferric chromium	1600-1750	3200-6000
Ferrous Tungsten Furnace	Tungsten crystal ore, coke	Ferro-Tungsten	2400-2900	3000-5000
Silicon chromium furnace	Ferric chromium, silica, coke	Silicon chromium alloy	1600-1750	3500-6500
Silicon Manganese Furnace	Manganese ore, silica, scrap iron, coke	Silicon-Manganese Alloy	1350-1400	3500-4000
Steel-making electric furnace iron	Ores, coke	Pig iron	1500-1600	1800-2500
Calcium carbide furnace	Limestone, coke	Calcium	1900-2000	1900-3000
Boron Carbide Furnace	Boron oxide, coke	Boron carbide	1800-2500	11000-20000

(1) The electric consumption values vary greatly with the composition of raw materials, the composition of manufactured products, and the capacity of electric furnaces. Here is the approximate value.

Free send inquiries to stella@hanrm.com if any needs.

Email: stella@hanrm.com Or stellarollingmill@gmail.com

Whatsapp/Wechat:+8615877652925

Website:  https://www.hanrm.com

More News You May Interesting:

Energy Saving and Emission Reduction in Steelmaking Production

Alkaline EAF( Electric Arc Furnace) Oxidation Smelting Process

Nine Ways to Save Electricity in Steel-making Electric Furnace

Energy Efficiency Control System of Submerged Arc Furnace

EAF Steelmaking Cleaner Production Technology

What is Metallurgical Equipment?

Roller Hearth Reheating Furnace

Classification of Electric Arc Furnace

Furnace Transformer – Electric Arc Furnace

Melting Features of Medium Frequency Electric Furnace 

Electric Arc Furnace VS The Intermediate Frequency Furnace

The Function and Working Principle of Rolling Mill Heating Furnace

How Does Electric ARC Furnace Work?(B)

How Does Electric ARC Furnace Work?(A)

What are the Advantages and Disadvantages of Blast Furnace?

Characteristics of Electric Arc Furnace Steelmaking

Walking Beam Reheating Furnace VS Push-steel Reheating Furnace

Why Intermediate Frequency Furnace cannot be Turned on Normally?

The History of Electric Arc Furnace

EAF Water-cooled Furnace Roof

EAF Water-cooled Furnace Roof

Purpose: Water-cooled furnace roof is used on ladle refining furnaces with a large capacity of high-power or ultra-high-power electric arc furnace and transformer to meet the needs of the modern steel-making process. It is one of the important components of modern metallurgical equipment.

Composition of equipment: Furnace roof body, smoke collecting hood device (or smoke exhaust elbow)

Structural features:

The water-cooled furnace roof can be divided into two types according to the smelting conditions: the water-cooled electric arc furnace roof and the water-cooled furnace roof of the ladle refining furnace. Both covers are tube-type dense row structures and are equipped with central roofs knotted with refractory materials.

The water-cooled roof of a steel-making electric arc furnace is usually conical and bench-shaped and can be multi-piece structure. Exhaust smoke is internal exhaust smoke, which is completed by a pipe-type exhaust bend.

The sidewall of the water-cooled furnace roof of the ladle refining furnace is usually cylindrical and the top is a conical bench, which is an integral structure. Exhaust smoke is external smoke, through the smoke collecting device auxiliary on the water-cooled furnace roof.

Hani Metallurgy is a Hot Rolling Mill manufacturing company working mainly in the area of the bar and wire rod mills, high-speed wire rod mills, high-speed rebar rolling mills, TMT rolling mills, flying shear, cold strip rolling mill, reheating furnace, induction furnace, intermediate frequency furnace, electric arc furnace, ladle refining furnace, blast furnace, continuous casting machine.

Free send inquiries to stella@hanrm.com if any needs.

Whatsapp/Wechat:+8615877652925

Email: stella@hanrm.com    stellarollingmill@gmail.com

Website:  https://www.hanrm.com

Three-phase AC Electric Arc Furnace

Three-phase AC Electric Arc Furnace

Three-phase AC electric arc furnace is the main equipment for smelting electric furnace steel.

(1) Electrical and Thermal Characteristics.

Although the law of DC arc formation is also applicable to AC arc formation, the instantaneous voltage of AC power supply varies and phase difference exists between three-phase electrodes, so AC arc has its own special law.

When the electrode is supplied with alternating current, the instantaneous current of the arc changes with time, and the instantaneous power changes with time because the instantaneous value of the supply voltage changes with time, which is a fluctuating arc and may also be interrupted temporarily, i.e. it may be a discontinuous arc. An arc can be considered as a current-carrying gas conductor, which is subjected to electromagnetic forces when in a magnetic field, resulting in arc deflection, the size, and direction of which conform to Ampere's law.

(2) Heat Transfer in Furnace.

Three-phase electric arc furnace belongs to the furnace with large capacity and energy consumption, so energy saving is a central issue in furnace thermomechanics.

The heat exchange objects in the electric arc furnace are the electric arc, the charge, and the lining (including the hearth and the top), which together form a closed system.

The electric arc is the heat source, the charge is the heating body, and the lining is the insulation, which isolates the charge and the arc from the outside atmosphere and reduces the heat loss. Under normal conditions, the amount of gas in the furnace is not large. In order to simplify the problem, its role in heat transfer in the furnace is not considered.

Heat exchange in an electric arc furnace is extremely complex. 

The following heat transfer processes take radiant heat transfer as the main one:

1) The arc radiates directly to the liquid level of the molten pool;

2) Surface radiation from electric arc to furnace lining;

(radiation from the inner surface of furnace lining to liquid level of the molten pool;

4) Radiation from surface to surface of lining;

5) The molten pool liquid radiates towards the inner surface of the furnace lining;

6) Conduction and convection heat transfer from the upper surface of the molten pool to the inside of the molten steel;

7) Heat dissipation through the lining, door, and water-cooled parts.

(3) AC Electric Arc Furnace Structure.

The complete set of AC electric arc furnace equipment for steelmaking consists of four parts: the main circuit equipment, the control equipment, and the dust removal equipment.

The main body of the electric arc furnace for steelmaking consists of several parts, such as a hearth, body, furnace cover, electrodes, elevating device, and tilting mechanism.

Determining the shape and size of the furnace body is an important work in the design of an electric arc furnace. The principle of determining furnace shape is to meet the requirements of the steel-making process first. Secondly, it is beneficial to heat exchange in the furnace with small heat loss and full utilization of energy. In addition, a longer lining life is required.

When working, the lining of the electric arc furnace is easy to be damaged due to the high-temperature radiation of the electric arc, the impact of the solid charge, scouring of liquid metal, and furnace shake. Therefore, the life of the lining becomes a technical and economic index of the electric arc furnace. At present, the life of the semi-water-cooled lining of domestic electric arc furnaces is generally between 150 and 300 furnaces.

The brick cover of the electric arc furnace has a circular water-cooled furnace cover ring welded from steel plates to support the refractory material. The furnace cover is arched with refractory (commonly used aluminum plaque in China). There are three symmetrically arranged electrode holes in the furnace cover. The lifetime of refractories for furnace cover is an important technical and economic index. Generally, in China, the service life of the furnace cover is about 100 stoves, and that of the full water-cooled (spray-cooled) furnace cover of Mario Steel Company can reach 5000 stoves.

Because the current entering the electric arc furnace is very large, taking a 10t furnace as an example, the current of each electrode reaches about 13kA, so good conductivity of the electrode is required. At the same time, it should be able to withstand high temperatures and have certain mechanical strength. Generally, a graphite electrode is used. Graphite electrodes are expensive and their consumption index directly affects the cost of steelmaking. The average consumption index of electrodes in China is about 7kg/t, and the advanced index is 4.5kg/t. South Africa uses an external jet cooling device, which reduces electrode consumption to 3.25kg/t.

Advantages of Three-phase AC Electric Arc Furnace

(1) energy concentration, surface power of molten pool up to 560~1200kW/m2, and arc temperature over 3000T; 

(2) The process has great flexibility, can effectively remove impurities such as sulfur and phosphorus, and is convenient for temperature control; 

(3) Compared with converter furnace, scrap steel can be used as furnace charge; 

(4) High productivity and low power consumption (smelting power consumption is 350~600kW h/t); 

(5) Small area and low investment cost.

Disadvantages of Three-phase AC Electric Arc Furnace

(1) More smoke and dust, 2.5~8kg falling steel dust; 

(2) High noise up to 90~120dB; 

(3) Arc flashing interferes with the power grid.

Hani Metallurgy is a Hot Rolling Mill manufacturing company working mainly in the area of bar and wire rod mills, high-speed wire rod mills, high-speed rebar rolling mills, TMT rolling mills, flying shear, cold strip rolling mill, reheating furnace, induction furnace, intermediate frequency furnace, electric arc furnace, ladle refining furnace, blast furnace, continuous casting machine.

Free send inquiries to stella@hanrm.com if any needs.

Whatsapp/Wechat:+8615877652925

Email: stella@hanrm.com    stellarollingmill@gmail.com

Website:  https://www.hanrm.com

Electric Arc Furnace Short Network | Heavy Current Line

Electric Arc Furnace Short Network | Heavy Current Line

EAF Short Network (heavy current line) is the general name of the connection application part of the secondary circuit in the main circuit of an electric arc furnace, also known as a high current line.

Short network refers to the high current carrying fluid from the low-voltage side outlet end of the electric furnace transformer to the electrode end, mainly including the compensator connected with the low-voltage side outlet end of the transformer, rectangular copper bar or conductive copper pipe, flexible cable, conductive copper pipe on the conductive cross arm or ordinary electrode arm, graphite electrode and the connecting parts between the above sections, such as fixed connecting base, movable connecting base, electrode holder and other parts.

Short network is an important part of electric arc furnace, and with the increase of electric arc furnace capacity and ultra-high power, the importance of short network is becoming more and more prominent The biggest characteristics of the short network are the short length and high current.

Generally, the development length of the short network of steel smelting electric arc furnace is about 20 ~ 30m, but the current flowing through it is very large, generally tens of thousands of amps. For large submerged arc furnaces, calcium carbide furnace, and other arc furnaces, the current value will be greater.

Due to such a huge current flowing through the short network conductor, the resistance of the short network conductor is bound to consume a considerable amount of active electric energy.

At the same time, the current establishes a strong alternating magnetic field around the conductor, and the alternating magnetic flux will inevitably produce self-induced electromotive force and mutual inductance electromotive force in the short network conductor.

On the one hand, the induced electromotive force offsets part of the power supply voltage and reduces the arc power; On the other hand, due to the inevitable asymmetry of short network conductors, the current is unevenly distributed along each conductor, and power transfer occurs between conductors and between phases, resulting in unequal three-phase arc power, resulting in uneven melting of furnace charge and uneven burning loss of furnace lining, reduction of furnace productivity, etc., which seriously affects the operation index of the whole electric arc furnace.

Due to the large current, there is a large electric force between the short network conductors proportional to the square of the current. Especially in the melting period, the current fluctuates greatly, and the impact force of mutual attraction and repulsion between the short network conductors is large, resulting in the shaking of the short network conductors, the easy loosening of the contact, the heating of the contact resistance, the oxidation and damage of the contact, and the cable swing and mutual friction damage the cable insulation.

Due to the high ambient temperature and dust of the short net, the insulation between the short net conductor and the furnace body is easy to be damaged. Once the short network fails, it will inevitably lead to the hot shutdown of the electric arc furnace, increasing the heat loss and reducing productivity.

Therefore, whether designers or users should pay enough attention to the short networks, pay full attention to the two aspects of the short net's electrical parameters and reasonable short net structure, we should pay attention to the design and selection of reasonable electrical parameters of short nets, so as to improve the technical and economic indexes of the equipment, ensure the advanced technology, and fully pay attention to the mechanical structure of the short net conductors, develop and select new reliable short net components, and adopt a reasonable short net structure. To ensure the reliable operation of the equipment.

Hani Tech is a Hot Rolling Mill manufacturing company working mainly in the area of bar and wire rod mills, high-speed wire rod mills, high-speed rebar rolling mills, TMT rolling mills, flying shear, cold strip rolling mill, reheating furnace, induction furnace, intermediate frequency furnace, electric arc furnace, ladle refining furnace, blast furnace, continuous casting machine.

Free send inquiry to stella@hanrm.com if any needs.

Whatsapp/Wechat:+8615877652925

Email: stella@hanrm.com    stellarollingmill@gmail.com

Website:  https://www.hanrm.com

Electric Arc Furnace Water Cooled Furnace Roof

Electric Arc Furnace Water Cooled Furnace Roof

Water Cooled Roof of electric arc furnaces developed and designed by Hani Metallurgy are of advanced water-cooled technology, reliable quality, and reasonable price. They are highly praised by the users and are preferred by the manufacturers of water-cooled furnace roofs.

Because high power operation increases the production capacity of the electric arc furnace, but also significantly increases the heat load of the refractory for the furnace roof, it is impossible to extend the service life of the furnace cover by improving the refractory. Therefore, water cooling technology is developed and rapidly popularized.

Water cooling technology started from the main furnace cover in the 1980s. The main furnace cover is water-cooled. The small furnace cover is bricklaying and prefabricated block of amorphous refractory, which reduces the consumption of refractory in the furnace roof by half to 1.5kg/t.

In the middle and late 1980s, water cooling was also used in the roof of the small furnace with low secondary voltage, thus realizing the full water cooling furnace roof. Now the electric furnace full water-cooled furnace roof has been widely used. Only the bricks around the electrode are made of refractory material. The consumption of refractory material for electric furnace roof has been reduced to less than 0.1kg/t.

The water-cooled furnace roof is welded with a boiler steel plate and the whole furnace cover is cooled by water. Only three-electrode holes in the water-cooled furnace cover are made of refractory or whole refractory prefabricates, or amorphous refractories, such as corundum castings, can be used to prevent the electrodes from striking against the water-cooled furnace roof and breaking it down.

The large furnace roof is a box-type or tube-type structure, while the small furnace roof is generally divided into the internal water-carrying structure. The water-cooled furnace roof designed by the Beijing Institute of Metallurgical Equipment Research has been in good operation since it was used in a 70tUHP electric furnace in Yongxin Iron and Steel Works of Zhangjiagang City in 1991. The cost per ton of steel has dropped significantly. The device consists of a water-cooled furnace roof and water-cooled furnace panel. The water-cooled furnace roof is a radial tube structure and is cooled by forced convection cooling water. The central part of the furnace roof is three-electrode holes made of refractory bricks. The service life of the small central furnace roof is about 300 times. There is a refractory covering on the inner wall and the upper surface of the furnace roof. Reinforcement bars are embedded in the coating to prevent the refractory from falling off. At present, the 30tUHP electric furnace of Great Wall Special Steel Company and the 50tUHP electric furnace of Fujian Zhongsteel Company has used this domestic water-cooled furnace roof, which has obtained good technical and economic benefits.

The integrated spray water cooling method was developed in the 1990s. The original box-type structure sometimes leaks when pressurized water is flowing through, so it is difficult to continue to use the tank with more water leakage. Spray water cooling is a turbulent flow formed with small water volume, which greatly increases the heat transfer coefficient and can be safely used with normal pressure water flow and small water leakage. The spray water cooling condition is suitable for the roof, panel, and smoke elbow of an ultra-high power electric furnace. The spray cooling furnace roof has good slag hanging performance. The service life of spray cooling roof of Plymenth plant in USA and Badishe plant in Germany exceeds 1000 furnaces, and that of Datong Steel Company in Japan reaches 9000 furnaces. The comparison between spray cooling and conventional cooling (furnace roof, furnace wall, and flue gas elbow) is shown in Table 2-1. The service life of refractories in the delta area of spray cooling furnace roof has been increased by about twice.

Hani Tech is a Hot Rolling Mill manufacturing company working mainly in the area of the bar and wire rod mills, high-speed wire rod mills, high-speed rebar rolling mills, TMT rolling mills, flying shear, cold strip rolling mill, reheating furnace, induction furnace, intermediate frequency furnace, electric arc furnace, ladle refining furnace, blast furnace, continuous casting machine.

Free send inquiry to stella@hanrm.com if any needs.

Whatsapp/Wechat:+8615877652925

Email: stella@hanrm.com    stellarollingmill@gmail.com

Website:  https://www.hanrm.com

DC Arc Furnace Steelmaking

DC Arc Furnace Steelmaking

In the mid-1980s, DC electric arc furnace steelmaking technology was developed abroad. Compared with AC electric arc furnace steelmaking technology, this technology has the following advantages:

1) The electrode consumption is reduced by more than 50%;

2) Reduce energy consumption per ton of steel by 5% ~ 10%;

3) The service life of furnace lining is extended by more than 30%;

4) The temperature of the molten pool is uniform and the fluctuation of tapping temperature is small;

5) The noise is reduced by about 10 dB;

6) The flicker is reduced by 50%, the interference to the power grid voltage is small, and the power grid capacity is 1 / 2 of that when using AC electric arc furnace, which can meet the requirements.

In terms of structure, the main difference between DC electric arc furnace and AC electric arc furnace is that a set of rectifier equipment is added to change the input power supply from AC to DC; The number of graphite electrodes on the top of the furnace is reduced from three to one, and a bottom electrode is added at the bottom of the furnace. 

From the perspective of investment benefit, although the infrastructure investment of DC electric arc furnace is about 20% higher than that of AC electric arc furnace, the payback period is greatly shortened. For example, if China transforms the old equipment of the original AC electric arc furnace into DC electric arc furnace, the cost will be recovered in about half a year.

To sum up, DC electric arc furnace has many advantages, and the development of DC electric arc furnace steelmaking technology has become a consensus. 

In the last 10 years, more than 40 DC electric arc furnaces of more than 50 tons have been put into production all over the world, with a maximum tonnage of 150 tons. Japan is building a 250 ton DC electric arc furnace, trying to be at the forefront of the world. 

The 30 ton DC electric arc furnace designed and manufactured by China has been put into production in Chengdu, Beijing, and other places, and the imported 100 ton DC electric arc furnace has also been built in Shanghai. 

It is estimated that more than 10 large DC electric arc furnaces will be completed and put into operation in China by 2000. This will lay a good foundation for the development of modern steelmaking technology.

Hani Tech is a Hot Rolling Mill manufacturing company working mainly in the area of bar and wire rod mills, high-speed wire rod mills, high-speed rebar rolling mills, TMT rolling mills, flying shear, cold strip rolling mill, reheating furnace, induction furnace, intermediate frequency furnace, electric arc furnace, ladle refining furnace, blast furnace, continuous casting machine.

Free send inquiries to stella@hanrm.com if any needs.

Whatsapp/Wechat:+8615877652925

Email: stella@hanrm.com    stellarollingmill@gmail.com

Website:  https://www.hanrm.com

Advantages of DC Electric Arc Furnace

Advantages of DC Electric Arc Furnace

DC electric arc furnace is a steel-making electric arc furnace that supplies electric energy with DC power. Like AC electric arc furnaces, it uses the arc produced between the electrode and the charge (or molten pool) to generate heat for the purpose of smelting and can be used to smelt steel or alloys.

The main advantages of DC electric arc furnaces over conventional AC electric arc furnaces are:

(1) The arc is stable and concentrated, the molten pool is agitated well, the temperature distribution in the furnace is uniform, and the lining erosion is small;

(2) Low fluctuation of current and voltage, less impact on the power grid, and longer cable life;

(3) Low electrode loss, 50% less electrode consumption per ton of steel than AC electric arc furnace. The performance of DC electric arc furnace is better than that of AC electric arc furnaces, but it has been hard to obtain a high-power DC power supply so it has not been developed for a long time.

(4) DC arc does not pass through zero point and has no periodic ignition and extinction, so the arc is stable.

(5) The graphite electrode of DC electric arc furnace acts as a cathode and the bottom electrode acts as an anode with fixed polarity. The heat generated by the arc mostly concentrates on the anode (i.e. the charge).

(6) DC electric arc furnace is generally a single electrode with only one arc burning vertically in the center of the furnace and no thousand disturbances and power transfer between the three phases.

Based on the above evaluation, DC arc characteristics are summarized as follows.

(7) The graphite electrode of DC electric arc furnace is only eroded at the end to form a circular recess.

(8) DC arc has no skin collection and proximity effects.

(9) Voltage drop of each section can be measured accurately.

(10) The electrode effect of DC electric arc furnace is very advantageous to charge heating. Under the same current condition, the heat produced by the anode effect is almost three times that of the cathodic effect.

(11) Mixing effect of DC electric arc furnace is much better than AC electric arc furnace, which makes the composition of steel more uniform.

The typical DC electric arc furnace includes a power supply, control system, short net, work, and bottom anode in addition to the outside of the furnace.

DC electric arc furnace has many similarities with ultra-high power AC electric arc furnace, such as scrap steel preheating equipment, oxygen-combustion nozzle, water-cooled oxygen gun, water-cooled furnace wall, and furnace cover, charging equipment, electrode lifting mechanism, and bottom blowing system, dust removal equipment, eccentric bottom tapping device, etc.

Hani Tech is a Hot Rolling Mill manufacturing company working mainly in the area of the bar and wire rod mills, high-speed wire rod mills, high-speed rebar rolling mills, TMT rolling mills, flying shear, cold strip rolling mill, reheating furnace, induction furnace, intermediate frequency furnace, electric arc furnace, ladle refining furnace, blast furnace, continuous casting machine.

Free send inquiry to stella@hanrm.com if any needs.

Whatsapp/Wechat:+8615877652925

Email: stella@hanrm.com    stellarollingmill@gmail.com

Website:  https://www.hanrm.com