Steel is typically melted in a foundry using electric furnaces, where carbon electrodes generate intense heat to turn solid steel into liquid.
Melting Steel in Foundries
In modern steel foundries, the primary method for melting steel scrap and alloys is through the use of electric furnaces. These furnaces are highly efficient and allow for precise control over the melting process and the final composition of the steel.
The core principle involves using electric energy to create the heat necessary for melting. As mentioned in the provided reference:
- The electric furnace uses electrodes dipped in the metal to generate the required heat.
- Specifically, the steel melting furnaces use carbon electrodes placed in the tank to charge the material directly until it melts.
This process usually refers to an Electric Arc Furnace (EAF). Here’s a breakdown of how it generally works based on this description:
- Loading the Furnace: Solid steel scrap, along with other materials like flux and alloying elements, is loaded into the furnace vessel (the "tank").
- Lowering the Electrodes: Large carbon electrodes are lowered from the furnace roof towards the charge material.
- Striking an Arc: A high electric current is passed through the electrodes. As the electrodes get close to or touch the metal charge, it creates a powerful electric arc between the electrodes and the steel. This arc generates extremely high temperatures, far exceeding the melting point of steel.
- Direct Heating: The heat generated by the electric arc is transferred directly to the steel charge. The reference highlights that the electrodes charge the material directly, indicating direct contact or close proximity leading to direct heating.
- Melting: As the temperature rises rapidly, the solid steel begins to melt, forming a pool of liquid metal at the bottom of the furnace. The electrodes may continue to be lowered as the scrap melts into the bath.
This method allows foundries to melt large quantities of steel quickly and efficiently, preparing it for casting into various shapes.
Key Components in Steel Melting:
- Electric Furnace: The main vessel where melting occurs.
- Carbon Electrodes: Conductors that carry electric current and create the arc.
- Steel Charge: The scrap steel and raw materials being melted.
- Electric Power Source: Provides the high voltage and current needed for the arc.
Using carbon electrodes to directly heat and melt the steel charge is a fundamental technique in electric arc furnaces, making them indispensable in the foundry industry.
