Classification of Ferrous Alloy Products
Ferrous alloys are composed of iron, carbon and other elements, and differ in terms of composition, properties and applications. This article provides a brief overview of the major types of ferrous alloys and their properties, as well as their applications in industry and everyday life.
Carbon steels are, as the name suggests, steels that contain carbon as their main alloying element. Carbon steels are among the most common and versatile ferrous alloys with numerous applications in a wide range of industries. Depending on their carbon content, they can have different properties, such as hardness, ductility, and tensile strength. Low carbon steels, with less than 0.3% of carbon by mass, are the most ductile and excellent for welding and other forming processes. These steels have very low wear resistance and are relatively weak. High carbon steels, with about 2% of carbon by mass, are hard and strong, with great wear resistance but are liable to cracking if not properly handled.
Alloy steels, sometimes referred to as tool steels, are steels that contain other metallic elements in addition to carbon to produce higher strength and increased toughness. Common alloying elements used in the production of alloy steels include manganese, chromium, vanadium, tungsten, and molybdenum. Alloy steels are typically used to manufacture tools, blades, and machine parts due to their enhanced wear and corrosion resistance.
Stainless steels, also known as rust-proof steels, are a group of ferrous alloys that provide exceptional resistance to corrosion. Stainless steels contain at least 10% of chromium, which is responsible for the alloy’s excellent corrosion resistance. Depending on the amount of chromium and other elements, stainless steels can achieve an array of properties and applications, including high-alloy stainless steels, austenitic stainless steels and duplex stainless steels.
Cast irons are among the oldest ferrous alloys and are comprised of iron, carbon, and silicon. Depending on their carbon content, cast irons can vary in strength, castability, and corrosion resistance. Low-carbon cast irons, also known as grey cast irons, are easy to cast and very machinable, but are not very strong. High-carbon cast irons, also known as ductile cast irons, offer excellent ductility and strength, making them ideal for applications where complex shapes are needed.
Pig iron is a type of ferrous alloy that is made from iron ore and carbon in a blast furnace. Through various processes including the addition of manganese and other alloying elements, it is further processed into more useful forms, such as steel, cast iron and ductile iron.
Malleable irons are special types of ferrous alloys produced through a process of heat treating and annealing cast iron parts. This makes them very hard and strong, as well as highly resistant to impact and wear without sacrificing ductility. Malleable irons are commonly used for the manufacture of railway parts such as wheels and rod ends.
These are some of the most common types of ferrous alloys and their properties and applications. Despite their individual characteristics and applications, all ferrous alloys share one common trait – rust resistance. All ferrous alloys have a protective layer of rust-resistant oxides on the metal surface, making them highly resistant to corrosion.
