What is the Difference Between Arc Furnace and Induction Furnace

The key difference between arc furnace and induction furnace is their heating and efficiency. The heat and efficiency of an induction furnace are comparatively higher than an arc furnace.

Arc furnaces and induction furnaces are important types of furnaces having many different uses in various industries.

CONTENTS

1. Overview and Key Difference
2. What is an Arc Furnace 
3. What is an Induction Furnace
4. Arc Furnace vs Induction Furnace in Tabular Form
5. Summary – Arc Furnace vs Induction Furnace

What is an Arc Furnace?

An arc furnace or electric arc furnace is a furnace useful in heating materials via an electric arc. There is a wide range of sizes of this type of furnace, and they range from small units to large units. These are used in research laboratories; they are also used by dentists. The temperature of these furnaces can reach up to 1800 degrees Celsius, and it can sometimes exceed 3000 degrees Celsius.

In this type of arc furnace, the charged material is typically exposed directly to an electric arc, where the current tends to form the furnace terminals to pass through the charged material. Moreover, these are different from induction furnaces that have the charge heated instead of eddy currents.

Typically, an electric arc furnace is useful in steelmaking, and it contains a refractory-lined vessel covered with a retractable roof, and there are one or more graphite electrodes that enter the furnace. There are three major sections of an arc furnace. The shell has sidewalls and a lower steel bowl. The hearth has the refractory that lines the lower bowl. Finally, there is the roof which is lined with refractory material, and we can shape it as a section of a sphere or as a frustum.

What is an Induction Furnace?

An induction furnace is a type of electric furnace having heat applied via induction heating of metal. It has a capacity that ranges from <1 kg to >100 tonnes. These are used in melting iron, steel, aluminum, copper, and other precious metals. The major advantage of this type of furnace is cleanliness and energy-efficient, and a well-controlled manner. These properties are very important compared to other types of metal melting.

Moreover, the induction furnace does not use an arc as in an electric arc furnace, combustion, or blast furnace. Thereby, the temperature of the charge is lower than the temperature needed to melt it. Therefore, the loss of valuable alloying elements is prevented.

However, there is a major drawback of induction furnaces; it lacks refining capacity. In other words, the charge materials are typically free of oxides and are well-known for their composition. There can be some alloying materials that are lost because of oxidation; thus, they are added again to the melt.

What is the Difference Between Arc Furnace and Induction Furnace?

The key difference between arc furnace and induction furnace is that the heating and efficiency of an arc furnace are low, whereas the heat and efficiency of an induction furnace are high. This is because the heat in the induction furnace is generated inside the molten steel (we call it a charge), which makes the heating comparatively fast. On the other hand, the heat produced by the arc is transferred to the molten steel via the slag, which is a type of indirect heating.

The below infographic presents the differences between arc furnace and induction furnace in tabular form for side-by-side comparison.

Summary – Arc Furnace vs Induction Furnace

An arc furnace is a furnace useful in heating materials via an electric arc, while an induction furnace is a type of electric furnace where heat is applied via induction heating of metal. The key difference between arc furnace and induction furnace is that the heating and efficiency of an arc furnace are low, whereas the heat and efficiency of an induction furnace are high.

Reference:

1. “Induction Melting Furnaces.” Induction Technology Corp., 30 Sept. 2022.

Image Courtesy:

1. “Electric Arc Furnace” By 0x24a537r9 – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Induktionstiegelofen Schnitt” By Christian Lindecke – Own work (CC BY-SA 3.0) via Commons Wikimedia