Material
Grey Iron
Grey Cast Iron is produced by remelting pig iron and is primarily an alloy of iron and carbon. It also contains small quantities of silicon, phosphorus, manganese, and sulfur. Its widespread use is largely due to its low cost and ability to form complex shapes with ease. These characteristics, along with its excellent mechanical properties, have made Grey Cast Iron one of the most commonly used metal alloys.
It is relatively affordable and offers advantages such as ease of casting—thanks to its expansion during solidification. One of its key features is the presence of free graphite in its structure, which acts as a natural lubricant and improves machinability. Grey Cast Iron also provides outstanding damping and wear resistance, making it ideal for components where high tensile strength and ductility are not essential.
Common applications include:
Equipment housings
Engine blocks
Valve bodies
Sliding components like hydraulic pistons
Stainless Steel
Stainless steel is an iron-based alloy containing at least 10.5% chromium. The presence of chromium forms a thin, protective oxide layer on the steel’s surface—known as the passive layer—which helps guard against further corrosion. Higher chromium content enhances this corrosion resistance. Stainless steel also includes varying levels of carbon, silicon, and manganese. Additional elements like nickel and molybdenum may be incorporated to improve properties such as corrosion resistance and formability.
Cast Steel
The physical characteristics of various types of steel and steel alloys are largely determined by the carbon content and how it is distributed within the iron. Iron alloys may contain carbon in a range from as little as 0.03% (as found in ingot steel) to as much as 2.08% by weight (as in cast iron), along with differing levels of other elements such as chromium, manganese, molybdenum, nickel, and silicon—based on their intended applications. Higher carbon levels enhance fluidity and castability, while lower carbon levels result in purer forms of steel ideal for specialized uses like stainless steel and electrical steel.
Ductile Iron
Ductile Iron—also known as SG Iron, Nodular Cast Iron, or Spheroidal Graphite Iron—is distinguished by the shape of the graphite in its structure. Unlike Grey Iron, which contains graphite in flake form, Ductile Iron features graphite as rounded nodules. This spheroidal graphite formation prevents the development of linear cracks, giving the material greater resistance to distortion.
It offers significantly higher tensile strength and ductility compared to Grey Iron. Depending on the grade, its mechanical properties can be tailored for a wide variety of applications, including load-bearing components. Ductile Iron often serves as a cost-effective alternative to steel, providing similar strength with easier machinability.
Key advantages:
High tensile strength and ductility
Versatility across multiple grades and applications
Ideal for structural and load-bearing uses
Cost-effective steel replacement
Easier to machine
Better corrosion resistance than many other ferrous alloys