The electric arc furnace for steelmaking consists of an elongated refractory container, cooled by water for large sizes, covered with a refractory dome and through which one or more graphite electrodes are housed inside the furnace. The oven is mainly composed of three parts:

The hearth can have a hemispherical or ovoid shape. In modern foundries, the furnace is usually raised off the floor, so the tub and weirs and ladles can maneuver on the base of the furnace. Separate from the furnace structure is the electrical system and electrode support, as well as the tilting platform on which the furnace rests.

A typical AC oven has three electrodes. The electrodes have a round section and usually segments with threaded couplings, so that as the electrodes wear, new segments can be added. The arc is formed between the charged material and the electrode. Thus the load is heated by both the current passing through the load and the radiant energy generated by the arc. The electrodes raise and lower automatically using a positioning system, which can use either electric forklifts or hydraulic cylinders.

The regulation system keeps the input current and power approximately constant during charge melting, even though the scrap may move under the electrodes as it melts. The arms of the electrode holding mast carry heavy bars, which may be hollow, with water-cooled copper pipes, carrying electric current to the electrode holdings. Modern systems use "hot arms", where the entire arm conducts the current, increasing performance. These can be made from copper-clad steel or aluminum. Since the electrodes move up and down automatically to regulate the arc and are raised to allow the oven dome to be removed, cables cooled by heavy water connect the bundle of tubes and arms to the transformer located next to the oven. To protect the transformer from heat, it is installed in a vault.

The furnace is built on a tilting platform so that the liquid steel is poured into another container for transportation. The operation of tilting the furnace to pour molten steel is known as "tapping." Originally, all steelmaking furnaces had a pouring spout, which was lined with refractory, which they relieved when tilted, but modern furnaces often have an eccentric bottom outlet (EBT) to reduce the inclusion of nitrogen and slag (metalworking slag) in the liquid steel. These furnaces have an opening that passes vertically through the hearth and frame, and is located off-center in the narrow "nose" of the oval hearth. Modern plants may have two frames with a single electrode system that can be transferred between the two frames; One frame preheats the scrap while the other frame is used for melting. Other DC-based furnaces have a similar arrangement, but have electrodes for each frame and a single electronic system.

There are AC furnaces that generally exhibit a pattern of heat and cold spots around the perimeter of the home, with the cold spots located between the electrodes. There are modern furnaces that mount oxygen fuel burners on the side wall and use them to provide energy to those cold spots, achieving more uniform heating of the steel. Additional chemical energy is provided by injecting oxygen and carbon into the furnace; Historically this was done through flamethrowers on the slag door, now this is done mainly through multiple injection equipment embedded in the wall.

A modern medium-sized steelmaking furnace has a 60 MVA power transformer, with a secondary voltage between 400 and 900 volts and a secondary current of more than 44,000 amperes.

In a modern shop, a furnace would have to produce a quantity of 80 metric tons of liquid steel in approximately 60 minutes of loading with cold scrap to take advantage of the furnace. In comparison, basic oxygen furnaces can have a capacity of 150-300 tons per batch, and can produce a batch in 30-40 minutes. There are huge variations in the details of kiln design and operation, depending on the final product and local conditions, as well as the latest studies to improve kiln efficiency. The largest dedicated scrap furnace (in terms of capacity and transformer size) is in Turkey, with a capacity of 300 metric tons and a 300 MVA transformer.

Producing one ton of steel in an electric arc furnace requires approximately 400 kWh of electricity per short ton, or about 440 kWh per metric ton. The theoretical minimum amount of energy required to melt one ton of scrap steel is 300 kWh (melting point 1520°C/2768°F). Therefore, such a 300 ton, 300 MVA electric arc furnace would require approximately 132 MWh of energy to melt the steel, and a "ignition time" (the time the steel melts with an arc) of approximately 37 minutes. Electric arc steelmaking is only profitable where there is abundant electricity, with a well-developed electrical grid.

The electric arc furnace for steelmaking consists of an elongated refractory container, cooled by water for large sizes, covered with a refractory dome and through which one or more graphite electrodes are housed inside the furnace. The oven is mainly composed of three parts:

The hearth can have a hemispherical or ovoid shape. In modern foundries, the furnace is usually raised off the floor, so the tub and weirs and ladles can maneuver on the base of the furnace. Separate from the furnace structure is the electrical system and electrode support, as well as the tilting platform on which the furnace rests.

A typical AC oven has three electrodes. The electrodes have a round section and usually segments with threaded couplings, so that as the electrodes wear, new segments can be added. The arc is formed between the charged material and the electrode. Thus the load is heated by both the current passing through the load and the radiant energy generated by the arc. The electrodes raise and lower automatically using a positioning system, which can use either electric forklifts or hydraulic cylinders.

The regulation system keeps the input current and power approximately constant during charge melting, even though the scrap may move under the electrodes as it melts. The arms of the electrode holding mast carry heavy bars, which may be hollow, with water-cooled copper pipes, carrying electric current to the electrode holdings. Modern systems use "hot arms", where the entire arm conducts the current, increasing performance. These can be made from copper-clad steel or aluminum. Since the electrodes move up and down automatically to regulate the arc and are raised to allow the oven dome to be removed, cables cooled by heavy water connect the bundle of tubes and arms to the transformer located next to the oven. To protect the transformer from heat, it is installed in a vault.

The furnace is built on a tilting platform so that the liquid steel is poured into another container for transportation. The operation of tilting the furnace to pour molten steel is known as "tapping." Originally, all steelmaking furnaces had a pouring spout, which was lined with refractory, which they relieved when tilted, but modern furnaces often have an eccentric bottom outlet (EBT) to reduce the inclusion of nitrogen and slag (metalworking slag) in the liquid steel. These furnaces have an opening that passes vertically through the hearth and frame, and is located off-center in the narrow "nose" of the oval hearth. Modern plants may have two frames with a single electrode system that can be transferred between the two frames; One frame preheats the scrap while the other frame is used for melting. Other DC-based furnaces have a similar arrangement, but have electrodes for each frame and a single electronic system.

There are AC furnaces that generally exhibit a pattern of heat and cold spots around the perimeter of the home, with the cold spots located between the electrodes. There are modern furnaces that mount oxygen fuel burners on the side wall and use them to provide energy to those cold spots, achieving more uniform heating of the steel. Additional chemical energy is provided by injecting oxygen and carbon into the furnace; Historically this was done through flamethrowers on the slag door, now this is done mainly through multiple injection equipment embedded in the wall.

A modern medium-sized steelmaking furnace has a 60 MVA power transformer, with a secondary voltage between 400 and 900 volts and a secondary current of more than 44,000 amperes.

In a modern shop, a furnace would have to produce a quantity of 80 metric tons of liquid steel in approximately 60 minutes of loading with cold scrap to take advantage of the furnace. In comparison, basic oxygen furnaces can have a capacity of 150-300 tons per batch, and can produce a batch in 30-40 minutes. There are huge variations in the details of kiln design and operation, depending on the final product and local conditions, as well as the latest studies to improve kiln efficiency. The largest dedicated scrap furnace (in terms of capacity and transformer size) is in Turkey, with a capacity of 300 metric tons and a 300 MVA transformer.

Producing one ton of steel in an electric arc furnace requires approximately 400 kWh of electricity per short ton, or about 440 kWh per metric ton. The theoretical minimum amount of energy required to melt one ton of scrap steel is 300 kWh (melting point 1520°C/2768°F). Therefore, such a 300 ton, 300 MVA electric arc furnace would require approximately 132 MWh of energy to melt the steel, and a "ignition time" (the time the steel melts with an arc) of approximately 37 minutes. Electric arc steelmaking is only profitable where there is abundant electricity, with a well-developed electrical grid.