What Is the Steel Manufacturing Process?

Steel is an important ferrous alloy — or metal made with iron and other elements — that is used in many tools, parts and products. The steel manufacturing process starts with mining iron or using scrap iron and purifying the materials in a reduction furnace. Once purified, the materials are mixed with other elements and placed into an electric arc furnace that alloys the elements together to create steel. Before the steel is collected, slag formed from the electric arc furnace is discarded. Steel is often poured into molds after the steel manufacturing process for whatever industry is purchasing it.

The steel manufacturing process begins with iron and scrap, which is placed into a direct reduction furnace. Iron is not pure in nature; instead, it is always combined with other elements, such as oxygen and sulfur. These other elements, known as impurities, make it impossible to properly alloy the iron into steel. By using a direct reduction furnace, the impurities are effectively burned away, leaving only pure iron to work with.

Once the iron is pure, the steel manufacturing process really starts. The iron, combined with about 1 percent carbon, is placed into a larger, more powerful furnace called an electric arc furnace. This furnace is lined with large electrodes that heat the iron with bursts of electricity until the iron and scrap melt.

When the electrodes cause the iron and carbon to melt, the two elements combine to make steel. On the surface of the steel alloy, there is a darker layer of material known as slag. Slag is a mixture of impurities that could not be reduced from the reduction furnace and is not usable in molds or other applications where steel is used.

The furnace is tilted in one direction to pour off the layer of slag, leaving only pure steel in the basin. The furnace is then tilted the opposite direction to pour the steel into a tap hole that collects the molten steel for later use. This concludes the steel creation process but not the steel manufacturing process.

Steel is then typically placed into molds for tools or parts, depending on the company purchasing the steel. The molten steel, in a liquid state, easily fills any mold. After enough steel is poured into the mold, cold water is used to cool and solidify the metal. The steel product is then shipped out to stores or businesses for use.