raakarautaa

Raakarautaa is a Finnish term that translates to "pig iron" in English. Pig iron is a high-carbon intermediate product of the iron ore smelting process. It is produced in a blast furnace by smelting iron ore with coke and a fluxing agent like limestone. The molten iron collects at the bottom of the furnace and is then cast into large ingots, which are called "pigs."

The defining characteristic of pig iron is its high carbon content, typically ranging from 3.5% to 4.5%. It also contains significant amounts of silicon, manganese, phosphorus, and sulfur. Due to its brittle nature caused by the high carbon content, pig iron is not suitable for direct use in most applications. Instead, it serves as a primary raw material for the production of steel and cast iron.

In the steelmaking process, pig iron is further refined to reduce its carbon content and remove impurities. This is commonly done in a basic oxygen furnace or an electric arc furnace. The resulting steel can then be alloyed with other elements to create a wide variety of steel grades with specific properties.

Cast iron is another important product derived from pig iron. It is produced by remelting pig iron, often with scrap iron, and recarburizing it to achieve a carbon content typically between 2% and 4%. Cast iron is known for its excellent castability, wear resistance, and vibration-damping properties, making it suitable for applications such as engine blocks, pipes, and cookware. The term "raakarautaa" thus signifies a foundational material in metallurgical industries.