An EAF Electric Arc Furnace is a sophisticated industrial facility used for melting and refining various types of metals, primarily steel. The EAF furnace operates on the principle of electrical energy being converted into intense heat through an electric arc. In the furnace, an electric arc is generated between electrodes and the metal charge, resulting in temperatures exceeding 3,000 degrees Celsius. This extreme heat causes the metal scrap or raw materials within the electric arc furnace to melt. Types of electric arc furnaces are widely employed in steel production due to their flexibility in handling diverse raw materials, including recycled steel. They offer advantages such as faster melting rates, precise temperature control, and reduced energy consumption compared to traditional methods, making the industrial electric arc furnace a pivotal technology in modern steelmaking processes.
The maintenance suggestion from the electric arc furnace EAF manufacturers in China
Reduction of the angle of tapping;
Simplify the tilting structure of the EAF furnace;
Reduce the copper busbar system impedance and increase life of the the electric arc furnace;
Retaining hot steel for slag operation;
No slag tapping, improves the quality of steel, is conducive to refining operations:
Hot heel & retain slag is conducive to EAF electric arc furnace treatment, and energy conservation;
Reduce the tapping temperature, save power consumption;
Reduce secondary oxidation and improve steel quality, increase ladle life of the steel making electric arc furnace.
EAF steel making usually can be divided into different category based on a different standard. Based on charging way, the electric arc furnace steelmaking can be divided into top charging EAF, horizontal and shaft continuous charging EAF. According to power supply, the electric arc steelmaking making can be divided into AC EAF, and DC EAF. Base on tapping direction, the EAF steelmaking can be divided into EBT and tapping spout.
located next to the melt shop. (Scrap generally comes in two main grades: shred (white goods, cars and other objects made of similar light-gauge steel) and heavy melt (large slabs and beams), along with some direct reduced iron (DRI) or pig iron for chemical balance.)
With 'clamshell' doors for a base. (Care is taken to layer the scrap in the basket to ensure good furnace operation; heavy melt is placed on top of a light layer of protective shred, on top of which is placed more shred. These layers should be present in the furnace after EAF charging.
The roof is swung off the steel mill electric arc furnace, and the furnace is charged with scrap from the basket. (Charging is one of the more dangerous operations for the EAF operators. There is a lot of energy generated by multiple tonnes of falling metal; any liquid metal in the steel arc furnace is often displaced upwards and outwards by the solid scrap, and the grease and dust on the scrap are ignited if the furnace is hot, resulting in a fireball erupting)
The EAF electrodes are lowered onto the scrap, an arc is struck and the electrodes are then set to bore into the layer of shred at the top of the arc furnace. Lower voltages are selected for this first part of the operation to protect the EAF roof and walls from excessive heat and damage from the arcs. Once the electrodes have reached the heavy melt at the base of the EAF furnace and the arcs are shielded by the scrap, the voltage can be increased and the electrodes raised slightly, lengthening the arcs and increasing power to the melt. This enables a molten pool to form more rapidly, reducing tap-to-tap times. Oxygen is also supersonically blown into the scrap, combusting or cutting the steel.
The scrap has been completely melted down, and another bucket of scrap can be charged into the electrode arc melt furnace and melted down. (After the second charge is completely melted, refining operations take place to check and correct the steel chemistry and superheat the melt above its freezing temperature in preparation for EAF tapping).
Burning out impurities such as silicon, sulfur, phosphorus, aluminium, manganese and calcium and removing their oxides to the slag. (Removal of carbon takes place after these elements have burnt out first, as they have a greater affinity for oxygen. Metals that have a poorer affinity for oxygen than iron, such as nickel and copper, cannot be removed through oxidation and must be controlled through scrap chemistry alone, such as introducing the direct reduced iron and pig iron mentioned earlier)
The electric arc steel is tapped out into a preheated ladle by tilting the arc furnace. During and after tapping, the electric arc furnace in steel making is 'turned around'. (the slag door is cleaned of solidified slag, repairs may take place, and electrodes are inspected for damage or lengthened through the addition of new segments; the taphole is filled with sand at the completion of tapping).
A major difference between the compared electric arc furnace EAF melting process is the ability to use differing quality charge materials. Oxidation and reduction reactions take place within and above the melt zone during electric arc furnace steelmaking, which allows for the usage of highly oxidized and low-quality scrap material. Induction furnaces are more sensitive to low-quality charge materials and contaminants, resulting in premium scrap costs. A reductive atmosphere is not present and therefore iron oxide will not be reduced. This increases iron loss through the slag. Another charge material difference between the EAF melting process is the cost of alloys and nonmetallic additions. An induction furnace operation uses a high-grade silicon carbide to adjust iron chemistry. In addition, pure carbon in the form of graphite is used for carburization. These additions are costs not required for the EAF.
EAF furnace process operation with state-of-the-art equipment has the following labour requirements: two EAF operators, one charge crane operator, and one foreman. This results in five workers per shift. A medium-frequency melt system's labour requirements are: two electrode arc furnace operators, two charger and crane operators, and one supervisor. Five workers per shift are required for melting within the outlined operation.
Thanks to faster equipment movements of the electric arc furnace for steel making including continuous casting furnace, EAF is advantageous for power-of-time in one-heat. Additionally, with chemical energy input by supersonic oxygen and carbon injection, the power-on time of EAF is lower. In general, the tap-to-tap time of EAF is around 50-60 minutes whereas, one heat can take 120-150 minutes for IMF. The profitability of any industrial plant increases and decreases directly with production rates.
Electric arc furnace steel making is a process that uses electric heating technology to melt and refine iron containing materials such as scrap steel into steel. Electric arc furnace EAF steelmaking occupies a dominant position in the production of special steel with small batches, multiple varieties, and high alloy ratios. CHNZBTECH, one of the leading steel furnace manufacturers, offers steelmaking EAF electric arc furnace with following advantages.
1. Environmental advantages: Electric arc furnace steel making can fully utilize the abundant domestic scrap steel resources, reduce raw material costs and environmental pollution.
2. Flexibility: Among types of steel making furnaces, electric furnace can achieve miniaturization, flexible production, and rapid adjustment to adapt to changes in market demand.
3. Technical advantages: In the electric arc furnace steel making process, the power input can be precisely controlled, and key parameters such as melting speed, smelting temperature, and furnace atmosphere can also be effectively controlled.
4. Economic advantages: Electric arc furnace steel making has low energy consumption, short construction period, and simple operation, resulting in low operating costs and strong adaptability.
Yes, EAF electric arc furnace steelmaking is high energy efficient. Because of higher electrical energy input with higher electrode current，higher electrical efficiency with reactors and thanking to additional chemical energy input (nearly 35 % oftotal energy) by oxy-fuel burners and C-injection, EAF operation requires lowest energy consumption around 380-420 kWh/ton.
EAF by means of arc melting scrap. Alternating current AC electric arc furnace has three moving graphite electrodes. Heating and melting of metal is enabled by radiant energy of the arc burning between the electrodes and metal, and the temperature in the arc zone reaches 4000 °C. The uniform burning of arc is regulated by means of moving of current-carrying electrodes transversely to the surface of the melt. It is possible to regulate the radiant energy by stretching and contracting the arc with two moving electrodes.
The use of EAF electric arc furnace including DC electric arc furnace allows steel to be made from a 100% scrap metal feedstock, commonly known as 'cold ferrous feed' to emphases the fact that for an EAF, scrap is a regulated feed material.The primary benefit of this is the large reduction in specific energy (energy per unit weight) required to produce the steel.
Another benefit is flexibility: while the electric blast furnace cannot vary their production by much and are never stopped, EAFs can be rapidly started and stopped,allowing the EAF steel mill to vary production according to demand.
Although steelmaking arc furnaces generally use scraps steel as their primary eedstock, if hot metal from a blast furnace or direct-reduced iron is available economically, these can also be used as furnace feed.
Yes, the electric arc furnace steelmaking requires oxygen, the use of oxygen in electric arc steelmaking has grown considerably.
In the past when oxygen consumption of less than 300 cubic feet per ton of steel were common, lancing operations were carried out manually using a consumable pipe lance by manipulator. Most modern operations now use automatic lances and most facilities now use a non-consumable, water-cooled lance for injecting oxygen into the steel. Many of these lances also have the capability to inject carbon as well.Oxy-fuel burners are now almost standard equipment on large high-powered furnaces. In operations with short tap-to-tap times, they provide an important function by ensuring rapid melting of the scrap in the cold spots.