When we talk about steel castings, we are usually referring to the metal casting or cast steel materials such as carbon steel and alloy steel, with carbon content of 2% or lower.

Cast iron, on the other hand, usually refers to gray iron, ductile iron and malleable iron, which often molded in the same or similar methods as steel castings, but with a carbon content above 2%.

The chemical makeup of steel castings and iron castings can sometimes be quite similar, but the function or mechanical properties of the two materials often varies significantly.

Steel Castings

Cast steel has is a highly-strength material suited to numerous critical engineering applications. By modifying your steel metallurgy and specifying different heat treatments, steel castings mechanical properties can be adjusted substantially.

Steel castings can be used for a variety of working conditions, and its mechanical properties are typically superior to most other metal casting alloys. For example, to withstand the high tensile stress demands or dynamic load requirements of different components, steel is often specified for pressure vessel castings in low or high temperature conditions.

Iron Castings

Gray iron castings (or gray cast iron) have good casting properties, good vibration dampening, moderate wear resistance, and moderate machinability with relatively low notch sensitivity. However, the drawback of gray iron is its tensile strength and elongation, both of which are very low. cast iron is suitable for producing some metal parts with low mechanical requirements, such as protective cover, cover, oil pan, hand wheels, frame, floor, hammer, small handle, base, frame, box, knife, bed, bearing seat, table, wheels, cover, pump, valve, pipe, flywheel, motor blocks etc.

Grey cast iron also has some high grades, so the grey iron castings with high grades can withstand greater load, and a certain degree of tightness and corrosion resistance. Such as cylinder, gear, base, flywheels, bed, cylinder block, cylinder liner (or cylinder sleeves), piston, gear box, brake wheel, coupling plates, medium pressure valve, etc.

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Ductile iron and malleable iron have higher strength, better ductility, heat-resistance and toughness than grey iron, so these materials have broader applications, and in some cases, ductile iron can replace carbon steel.

Considering its mechanical advantages, here are many fields where ductile iron is used, such as pressure pipes and fittings, Automotive applications, Agriculture, road and construction applications, General engineering applications.

Exploring the Differences Between Cast Iron and Cast Steel

Understanding the differences between cast iron and cast steel is crucial for selecting the appropriate material for specific applications. Cast iron typically features a higher carbon content—over 2%—which contributes to its excellent machinability and vibration dampening properties, making it suitable for parts like machine frames, engine blocks, and cooking utensils. On the other hand, cast steel, with a carbon content of 2% or lower, boasts superior tensile strength and durability. This makes steel castings ideal for high-stress applications such as structural supports, mining equipment, and heavy-duty machinery.

Material Characteristics and Usage in Industry

The choice between cast iron and cast steel often depends on the balance between cost, performance, and longevity required by the application. Cast steel’s ability to withstand high impact and shock at low to high temperatures allows it to be used in demanding engineering contexts where a high degree of precision is needed. Meanwhile, the high carbon content in cast iron, while limiting its strength relative to cast steel, provides excellent wear resistance and the ability to absorb sound and vibration. These properties make cast iron a preferred material in industries where these characteristics are prioritized, such as automotive components and large infrastructure projects.