Common Heat-Resistant Cast Iron Grades
1. Grey Iron
Grey iron is a ductile product produced from pig iron. It contains 3.5-4.5% carbon and can contain silicon, manganese, and sulfur. Grey iron has both superior strength and wear resistance, making it an ideal choice of material for many automotive, industrial machine parts, and fluid pumps. It has a balanced combination of both ductility and high strength which makes it resistant to fatigue and impact loading.
2. White Iron
White iron is a form of cast iron that has a higher carbon content than grey iron. It can contain up to 7.5% carbon, as well as chromium, nickel, and other metals. This combination of elements results in a strong, wear resistant material that is ideal for industrial parts exposed to friction, such as axles and valves. Despite its strength and durability, white iron remains malleable and can be bent and formed into different shapes without cracking or breaking.
3. Ductile Iron
Ductile iron is a form of cast iron whose composition has been altered to improve the malleability and strength of the material. Ductile iron is comprised of iron, carbon, and small amounts of magnesium and other elements to increase the strength and ductility of the material. It has superior wear resistance and fatigue strength, making it an ideal material for high-load bearings and components.
4. Hammered/Compacted Graphite Iron
Hammered or compacted graphite iron is a form of cast iron produced by rapidly compressing it under high pressure. This process results in a material that is more malleable but still maintains a high tensile strength. Its wear resistance and resistance to fatigue makes it an ideal choice for components exposed to high impact and vibration.
5. Malleable Iron
Malleable iron is a type of cast iron that can be bent, formed, and shaped without cracking. It is produced by a process of heat treating and annealing the iron which transforms its original crystal structure from iron and carbon to a spheroidal form. This increased malleability makes it an ideal material for components such as brackets, pins, and fasteners.
6. High Alloy Iron
High alloy iron is a form of cast iron that includes several elements to improve the strength and wear resistance of the material. It can contain nickel, molybdenum, chromium, and copper which improve the strength of the material while providing excellent wear and corrosion resistance. High alloy iron is commonly used in components such as levers, bushings, and bearings.
7. Austempered Iron
Austempered iron is a type of cast iron that has been treated with a special process to improve the strength and wear resistance of the material. This process involves heating the iron and then cooling it slowly in a controlled atmosphere, resulting in a material that is far more wear resistant and impact resistant than other types of cast iron.
8. Ni-Resist Iron
Ni-Resist iron is a form of cast iron that may include up to 8% nickel. A high amount of nickel provides the material with excellent corrosion and wear resistance and is an ideal material for components that are exposed to harsh environments, such as valves and pipes.
