Cast Iron Vs Steel: Differences Between These Metals and Pros and Cons

Metals play a pivotal role in the realm of manufacturing. Many manufacturers opt for metals such as iron and steel due to their distinct qualities, encompassing attributes like strength, longevity, and the capacity to maintain their luster over prolonged periods.

Nevertheless, despite the comparable appearance of metals like cast iron and steel, they stand apart in significant ways. In essence, these two metals possess unique features that can either confer benefits or drawbacks to a production process.

Would you like to delve into the distinctions between cast iron and steel? Is steel inherently superior to iron in terms of strength? Peruse ahead as we furnish elucidations to these inquiries, in addition to outlining the merits and demerits associated with each of these two metals.

What’s Cast Iron?

This iron is made through smelting iron-carbon alloys. The carbon content of this alloy is often between 2-4%. To clarify, the cast iron has a carbon content higher than 2%. Furthermore, after the smelting process, the ironsmith pours the iron into a mold instead of working the iron with a hammer and tools.

Aside from carbon content, cast iron also contains 1-3% silicon, improving its casting performance. Besides, it contains trace amounts of manganese. Impurities like phosphorus and sulfur may also be present. The few common mechanical properties of cast iron include hardness, elasticity, ductility, and toughness.

There are different types of this brittle material, with the differences arising due to the different processing techniques and heat treatments employed during the process. The different types of cast iron include：

• Gray Iron
• White Iron
• Malleable Iron
• Ductile Iron
• Compacted graphite iron

What’s Steel?

This type of iron is produced through smelting iron-carbon alloys with a carbon content that often falls between 2-4%. To clarify, cast iron specifically possesses a carbon content exceeding 2%. Post the smelting process, instead of employing hammers and tools, the ironsmith pours the molten iron into molds.

Besides carbon, cast iron is also infused with 1-3% silicon, enhancing its casting performance. It also contains trace amounts of manganese. Some impurities like phosphorus and sulfur might be present. Notable mechanical properties of cast iron include hardness, elasticity, ductility, and toughness.

Different variations of this relatively brittle material emerge due to varied processing techniques and heat treatments applied during production. Various cast iron types encompass:

• Carbon Steel
• Alloy Steel
• Stainless Steel
• Tool Steel

Carbon Content

The key difference between cast iron and carbon steel is their carbon content. Cast iron contains over 2% carbon, while steel has less than 2% carbon. Steel can also include additional elements like chromium, leading to diverse grades and qualities.

Melting Point

Cast iron has a lower melting point than steel. Its melting point is 2200 degrees Fahrenheit, whereas steel’s range is 2500-2800 degrees Fahrenheit. This lower melting point of iron enables easy shaping into different forms.

Strength

Both materials exhibit strength, although their strengths differ. Cast iron possesses greater compressive strength than steel. In contrast, steel boasts higher tensile strength than cast iron, enabling it to flex without fracturing. To elucidate, the inherent compressive strength of iron imparts exceptional hardness, rendering it resilient against dents and bending. However, its drawback lies in its proneness to fracture under excessive pressure.

Castability

Cast iron exhibits greater casting ease compared to steel due to its enhanced flowability and minimal shrinkage. Conversely, steel is characterized by reduced fluidity, responsiveness to mold materials, and contraction during cooling. To expound, steel possesses relatively higher viscosity. The uncomplicated casting process associated with iron renders it an ideal choice for intricate ironwork structures.

Corrosion Resistance

Although their appearances may resemble each other, cast iron exhibits superior resistance to corrosion and rust when compared to steel. Nevertheless, it’s important to note that neither of these metal materials is entirely immune to corrosion. If left exposed and lacking protective measures, both materials can undergo oxidation, ultimately resulting in their deterioration.

Impact Resistance

Steel is better at resisting impact better than cast iron. This is especially true for sudden impacts. With sudden impacts, steel does not bend, break or deform as quickly as cast iron.

Cost

Cast iron is cheaper than steel because of the lower cost of material needed to produce cast iron. Furthermore, producing raw steel requires more labor and energy consumption.

Applications

These materials find distinct applications based on their unique properties. Cast iron finds suitability in crafting pipe fittings, washers, agricultural machinery, machine components, mining hardware, electrical fixtures, and hand tools. In contrast, steel is well-suited for producing tools, weaponry, electrical devices, vehicles, and various types of infrastructure.

Cast Iron Vs Steel: Which One to Choose?

Choosing between these metals will require knowing the pros and cons of both metals. Below are their advantages and disadvantages.

Advantages and Disadvantages of Cast Iron

Advantages

• Good casting ability
• Available in large quantities, making production relatively inexpensive.
• It has a high compression strength
• Cast irons have good machinability
• Good anti-vibration property
• It has excellent wear resistance
• Low-stress concentration
• High resistance to deformation
• High durability

Disadvantages

• Prone to corrosion and rust
• Low tensile strength
• High  impact resistance
• High weight-to-strength ratio
• High brittleness

Advantages and Disadvantages of Steel

Advantages of Steel

• Increased flexibility in design, as you can choose the alloy element you want to combine with steel
• Increased strength
• Resistant to corrosion
• Easy machining

Disadvantages of Steel

• More expensive than cast iron
• Less resistant to impact

So, between cast iron vs steel, Which do you prefer? Having seen the advantages and disadvantages of both types of materials, the one you ultimately choose to use would be dependent on your product requirements.

While we understand that you may have your own preferences when it comes to the choice between cast iron and steel, finding the right metal casting service for prototyping and production may be another challenge you need to face.

XY-global is your ideal partner to handle the prototyping and production of metal products and parts. Our specialised die casting services, as well as other casting services, will ensure that you get the best metal parts with high productivity and stringent quality control. In addition, we offer a wide range of metal materials to choose from to ensure high-quality metal parts for your products.

What’s more, once you email us your project, you’ll receive a free quote and design for manufacturing analysis (DFM analysis).