How much do you know about cast iron?

Cast iron has been known for hundreds of years, but it was during the last century that it experienced its most important change.

Starting in 1940, work began with continuous casting processes and with different alloys. Everything arises as new alternatives to the competition of steels for different applications.

Let us remember that a steel corresponds to an alloy of Iron and Carbon, where carbon can be present up to 2.0% if it is greater than 2.0% and up to 6.67%, they are called iron castings, in addition to containing amounts of silicon of 0.3%. and other compounds such as sulfur and phosphorus.

Cast iron or cast iron is known as gray cast iron, which is one of the most used ferrous materials and its name is due to the appearance of its surface.

A distinctive characteristic of gray iron or cast iron is that the carbon is generally found as graphite, taking irregular shapes described as “flakes” that cause low tensile strength and ductility.

Cast Iron Classification 

1.  Gray Cast Iron contains graphite in the form of flakes that cause low tensile strength and ductility.

2.   Ductile, or spheroidal, cast iron contains spheroid particles of graphite, generated during solidification.

Laminar or pearlitic casting in cast iron

It is the quality with the highest hardness (200-250 HB) and is therefore used when high tensile strength and/or wear resistance is required due to its pearlitic structure. Its surface finish will be superior to other qualities of lower hardness and due to its greater structural cohesion. Supports surface tempering.​

This pearlitic smelter is of great industrial interest. The microstructure formed by alternating layers or sheets of two phases (ferrite and cementite) is called pearlite. It has good moldability and resistance to abrasion but is nevertheless fragile.

To obtain this type of foundry, which is more than 90% of all foundries, silicon (or graphitizing elements such as phosphorus, aluminum, nickel or copper) is needed.

Marketing of Special Steels

This material is a high strength cast iron, known for its remarkable ability to resist wear, making it a preferred choice in applications requiring extreme durability. In addition, it has the advantage of being susceptible to heat treatments, such as Temple and the tempered, allowing it to reach hardness levels comparable to those of steel. This process further improves its mechanical properties, strengthening its overall strength and increasing its lifespan. Unlike other materials, this type of iron has an exceptional ability to reduce noise and vibration of the parts manufactured with it, which is crucial in many industrial applications where acoustic comfort and structural stability are a priority.

This type of cast iron is known as highly pearlitic iron, which means that it has a microstructure composed predominantly of pearlite. This crystalline structure gives it considerable hardness, which can vary depending on the size and shape of the parts produced with it. Supply hardnesses can be adjusted according to application requirements, making this material a versatile option for a wide range of industrial needs. Its ability to balance hardness with machinability makes it an optimal solution for applications that require precision in the machining process.

One of the most outstanding features of this type of cast iron is its superior machinability compared to any other ferrous material, including 12L14 steel, which is known for its excellent machinability. In milling and turning processes, this cast iron allows for greater ease and speed in manufacturing, reducing wear on cutting tools and improving operational efficiency. In addition, it combines optimal levels of impact and fatigue, which means it can withstand high repetitive stresses without fracturing, making it ideal for high-demand applications in industry.

Another important property of this cast iron is its good conductivity, making it useful in situations where a balance between mechanical strength and thermal or electrical transfer is required. At the same time, its ability to dampen noise and vibration is especially notable. This feature sets it apart from other ferrous materials, as it helps reduce the propagation of unwanted vibrations in machinery, engines or structures, providing a quieter environment and reducing wear from vibration. These properties make it an unrivaled choice for applications that demand robust mechanical performance along with the ability to mitigate noise and vibrations.

Due to its ferritic structure, it is not intended for a quench-hardening process.​

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