Table of Contents
The differences between cast iron and steel are many. The main comparison point of cast iron vs steel is the carbon content present in these materials. There are multiple other distinguishing features including properties and applications.
Before we learn the differences, let us have a look the definition of cast iron and steel:
What is steel?
Steel is an alloy of iron. The steel manufacturing process starts with iron being mixed with coke and coal at high temperatures to form molten steel. This molten steel is then hot-rolled or cold rolled in a rolling mill to create the desired shape like steel coils, slabs, billets etc.
There are different types of steel including:
- Carbon steel
- Alloy steel
- Stainless steel
- Tool steel
What is cast iron?
Cast iron is an alloy of iron with carbon composition ranging from 2% – 4%. Silicon is another alloying element found in cast iron with a rough percentage of around 1-3% by weight. Different types of cast iron include:
- Malleable iron
- Ductile iron
- White iron
- Gray iron
- Compacted graphite iron
Cast iron vs steel: Differences
Have a look at differences between cast iron and steel:
| Features | Cast iron | Steel |
| Definition | Alloy of iron with 2%-4% carbon content | Alloy of iron with less than 2% carbon content |
| Form of carbon | Graphite, iron carbide or both | Iron carbide |
| Melting point | Lower than steel (1150° -1300° Celsius) | Higher than cast iron (1425 °– 1540° Celsius)
|
| Strength | More compressive strength | More tensile strength |
| Castability | Easy to cast due to low shrinkage | Less easy to cast compared to cast iron due to more shrinkage |
| Machinability | Hard to machine | Easy to machine |
| Ductility | More brittle than steel | Relatively less brittle |
| Fluidity | Excellent fluidity | No fluidity |
| Corrosion resistance | More corrosion resistant than steel | Less corrosion resistant |
Let us have a look at the explanations of a few of the following terminologies mentioned in the above table:
- Castability
Castability refers to the ease with which a metal can be cast into different shapes and sizes from its liquid state. For eg; steel in its molten form can be cast into various products cast steel.
- Machinability
Machinability refers to the ease of machining of materials. This implies the ease with which a metal can be cut, depending on its physical properties. Metals with higher machinability require less power to cut and can be processed more quickly.
- Fluidity
Fluidity is the ability of a molten metal to fill mold cavities. Poor fluidity causes manufacturers to increase the pouring temperatures of the molten metal which in turn affects the quality of the casting process.
Steel vs cast iron: Weight
The density of cast iron is typically 6,800 – 7,800 kg/m3 depending on the carbon content and other impurities present. The density of steel on the other hand varies according to the type of steel. The density of high carbon steel is 7,840 kg/m3 while the density of stainless steel is 8000 kg/m3.
Applications of cast iron and steel
Uses of steel include:
- Buildings and infrastructure
- Automotive parts
- Mechanical equipment
- Surgical instruments
- Food processing equipment
Applications of cast iron includes:
- Machine parts, hand tools, brackets, pipe fittings, farm equipment and mining hardware
- Pipes to carry suitable fluids
- Automotive parts such as bearing caps, steering-gear housings, differential carriers and differential cases
- Anchors for ships
- Pots, pans and other cooking utensils
Cast iron and steel are used in a variety of ways for industrial purposes. Since cast iron is easy to mould they can even be found as decorative artwork on buildings. Cast iron and steel prices in India vary according to market conditions and the products you order. Steel prices also depend on the grade of steel you choose for your products.
If you are looking for information on daily steel prices and quality steel suppliers, do visit Tata nexarc’s Procurement platform, a one-stop solution for all your steel needs. We have partnered with reputable steel vendors across the country to match the steel requirements of every small business at budget-friendly prices.
