How are graphite electrodes used for EAF steelmaking?

The process of electric arc furnace steelmaking is complex and highly technical, but the basics are easy to understand. Graphite electrodes used in eaf, which generate heat to melt iron ore and other materials and extract pure iron from them to make steel. Electric arc furnaces work similarly to traditional blast furnaces, except they use electricity rather than coal or natural gas as their energy source. In this article, we’ll explore graphite electrodes used in electric arc furnaces, who uses them and why, how much current passes through a typical EAF electrode, and how long they last before needing replacement.

How are graphite electrodes used for EAF steelmaking steel production?

Graphite electrodes are used in electric arc furnace (eaf) as a carbon source and conductor for steelmaking. Electric arc furnaces refine iron and produce steel, providing the heat necessary to melt iron ore, remove impurities from the molten iron product, and create slag that separates from purer metal.

Плавлення сировини:

В електродугових печах використовуються графітові електроди, які генерують інтенсивне тепло за допомогою електричної дуги. Електроди вертикально вставляються в ЕДП, і коли через них проходить електричний струм, він створює високотемпературну дугу між електродами і металевою шихтою всередині печі. Ця дуга швидко нагріває і плавить сировину, включаючи сталевий брухт та інші металеві компоненти, перетворюючи їх у розплавлений стан.

Сприяння процесу рафінування сталі:

Once the raw materials are melted, graphite electrodes continue to play a crucial role in the refining stage of eaf steelmaking. During this process, various operations are performed to adjust the chemical composition, remove impurities, and control temperature. They provide the necessary heat and electrical conductivity to carry out these refining processes effectively.

Безперервне лиття:

In the final stage of steelmaking, where the molten steel is cast into various shapes, graphite electrodes are utilized in continuous casting processes.

They help maintain the temperature of the molten steel and prevent premature solidification during the casting process. Electrical current is also provided to promote solidification and form a solid steel product.

What are the grades of graphite electrodes used for eaf steelmaking?

The most commonly used grades in EAF include: UHP、HP and RP. Graphite electrodes are made from нафтовий кокс and pitch coke, mixed with a binder, and pressed into a mold. The production of HP and UHP grades uses needle coke as the raw material. The production process uses multiple impregnation and roasting to increase the graphitization temperature and improve the binder and impregnant accordingly. Generally, according to the tonnage of the electric arc furnace, the electrodes of the specifications are selected for use.

How much current passed through ?

Сила струму, що проходить через типовий графітовий електрод, зазвичай знаходиться в діапазоні 10-20 А. Наприклад, великий електрод може мати щільність струму of over 100 A/cm2.  Because it has low resistivity and is a good conductor.

Який тип сталі виробляють в електродугових печах (ЕДП)?

Steel is made by extracting the iron and adding carbon when iron ore and coke are heated to a temperature of 2,700°F (1,500°C) in an electric arc furnace (EAF).

The types of steel produced include carbon steel, alloy steel, cast steel, pure iron and alloys, etc.

Висновок

Graphite electrodes have high electrical conductivity, heat resistance and mechanical strength. So it is ideally suited for eaf steelmaking, refining and casting processes. It has become an indispensable conductor electrode for modern electric arc furnace steelmaking.