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Iron is an essential metal with widespread use. It is used everywhere, from homes to construction sites, the transportation industry, fashion, etc. Iron’s wide application is perhaps due to its abundance on the earth. Despite the widespread use of iron, it’s possible to get confused about the types of iron to use for your projects.
If you’ve ever contemplated using iron for a project, this blog post is for you. This guide will explain in detail all you need to know about the different types of iron, their advantages and disadvantages. You will also learn the differences between the main types of iron and their uses to help you choose the iron suitable for your project.
What Are the Different Types of Iron?
Iron are of various types and they each have different characteristics and specific applications. They include:
1. Cast Iron
Cast iron is an iron alloy with a 2-4% carbon content. It also contains 1-3% silicon and a small quantity of manganese, this helps improve the performance of the casting process. Some other adulteration like sulfur and phosphorus may also be present. In its manufacturing process, cast iron is created by smelting iron-carbon alloys.
It is then poured into molds so that upon solidification, it takes the shape and form of the mold. Different techniques like heat treatment are employed in the manufacture of cast iron, from which other subtypes of cast iron are obtained like Gray Iron, White Iron, Malleable Iron, Ductile Iron, and Compacted graphite iron.
Pros
Some of the pros of cast iron include:
- High compressive capabilities: Cast iron is excellent under compressive weights. This makes it suitable for heavyweight because of its structural integrity and durability.
- Thermal conductivity: It conducts heat effectively and forms the basis of its use in kitchenware and engine part applications. Aside from conducting heat effectively, cast iron also has quality heat retention.
- Corrosion resistance: Cast iron has intermediate-level resistance to corrosion. You can reduce its corrosion exposure by preventing cast iron contact with acid.
- Damping capacity: Due to the molecular structure of cast iron, large carbon crystals are locked up in the structure, preventing the movement of iron. This structural advantage supports the use of cast iron in absorbing vibration.
Cons
These are some of the cons of cast iron.
- Brittle: Cast iron is brittle due to its high carbon component, which results in easy fracturing.
- Rust: Although cast iron has an intermediate-level corrosion resistance, it rusts easily under extreme conditions, such as acid exposure.
- Low tensile strength: Cast iron has low tensile strength and poses significant safety challenges because of its heavy weight when used in manufacturing.
Uses
Cast iron has applications in the:
- Construction industry: where it is the go-to iron due to its heavyweight characteristics. It is used in the construction of buildings, foundations, columns, and bridges.
- Automotive industry: it is used for automotive parts like engine blocks due to its heat retention capabilities, ability to take different forms, and cost-effective production.
- It also has an application in the construction of gearboxes and gear trains because of its ability to absorb vibration and remain stiff.
- Used in making cylinder heads and brake rotors for its low thermal expansion and high strength that reduces the odds of tire hazards, as seen in loosening and twisting of tires.
- Pipes and fittings: cast iron is used in industrial water systems for its longevity and ability to take the shapes usually required of pipework parts.
- Cookware: it is used in the manufacture of skillets and fry pans for its excellent heat distribution properties.
2. Wrought Iron
Wrought iron is one of the iron alloys that has a very low carbon content which is less than 0.05%, unlike cast iron. It is tough, corrosion-resistant, ductile, and malleable, and can be forged easily. However, it is challenging when you want to weld it electrically. Due to its low carbon content, it can’t be hardened enough when you heat and quench it.
Wrought iron is greatly purified with a small quantity of silicate slag, which is forged out into fibers. It contains 99.4% iron by mass. This slag is advantageous to blacksmiths in forge welding because the silicate inclusion performs as a flux which gives the material its special fibrous structure.
Pros
Wrought iron has the following advantages:
- Durability: Due to its inherent corrosion resistance, wrought iron is long-lasting and suitable for outdoor structures exposed to harsh conditions.
- Versatility: Its properties make it suitable for use in various processes.
- Low maintenance cost: Because wrought iron can exist for years without losing its structural integrity and aesthetics, it requires a lower cost of maintenance.
- Biodegradable: Wrought iron is reusable, free of environmental risks, and can be refurbished by subjecting it to a re-manufacturing process. In the process of remaking, wrought iron can be made into another shape by heating it, then hammering and bending it into a desired shape.
Cons
Drawbacks of wrought iron include:
- Cost-intensiveness: It is cost-intensive because it is made by hand and using designated tools. This labor-intensive practice accrues cost.
- Longer manufacturing time: Due to its labor-intensive characteristics, there is usually a more extended production period than other irons. This implies that you should exercise more patience when requesting wrought iron products from manufacturers.
- Application limitation: Wrought iron is not usually produced in large quantities like other metals. As a result, its bulky use can be limited in the manufacture of extensive gates and staircases.
Uses
Wrought iron has the following uses:
- For aesthetics: because wrought iron can be bent and structured into complex patterns, it is applied for decorative purposes. Furthermore, it is suitable for aesthetics because of its timeless appearance.
- Balconies: dating back to the twentieth century in ancient cities like Rome, and even in contemporary times, wrought iron has been used to make hand railings and balcony supports.
- Ornamental railings: Wrought iron is traditionally used to make gates and railings because of its architectural suitability. It is also used in-house to make chairs and tables.
- The wrought iron application extends to construction, where it was used to support beams before the emergence of newer construction irons.
Ductile Iron
Ductile Iron, also known as nodular iron, is a group of materials, not just a single one. Its unique properties are achieved by controlling the microstructure during production. In addition to iron, elements like silicon, carbon, manganese, magnesium, and copper are also present in ductile iron.
The composition of ductile iron consists 2.3 to 3.6% carbon and 2.2 to 2.8% silicon, along with other iron components. Magnesium is especially important, as it acts as a nodulizing agent. By adding magnesium, the process strengthens the ductile iron structure and promotes the formation of spherical shapes that are less likely to fracture.
The effect is that ductile iron has a more remarkable ability to resist deformity with stress, high tensile strength, and excellent elongation capabilities. You can adjust the ductile iron components to obtain different iron types. This adjustment process would involve regulating the heat applied and the extent of the magnesium added.
Pros
Some of the advantages of ductile iron include:
- Mechanical properties: Ductile iron is most known for its ductility and has a superior tensile strength of 400 to 900 MPa. It has excellent elongation capacity and extensive toughness.
- Stress endurance and deformation resistance: Due to the high tensile strength of ductile iron, it can resist breaking and withstand intense stress without cracking.
- Cost-effectiveness: Because of its extensive durability and high tensile strength, there is a reduced need for replacement, reducing the overall maintenance cost. Additionally, ductile iron production is such that it is not handmade, so you can manufacture it on a large scale and reduce production costs.
Cons
Disadvantages of ductile iron include:
- Low thermal conductivity: Ductile iron does not effectively conduct heat, so it is not the choice iron for applications that require heat dissipation.
- Design limitations: Although ductile iron can be shaped into desired designs, it can suffer poor mechanical features and defects should it be used to manufacture iron components of thin dimensions.
- Corrosion: Ductile iron deteriorates faster when exposed to environmental conditions like acid and moisture. To reduce corrosion and enhance durability, you should coat it with protective agents.
- Weighty: Ductile iron is heavy compared to many other irons. This limits its application for lightweight use, as seen in the aerospace industries. It also increases its transportation cost and poses safety concerns when large ductile iron forms are being handled.
Uses
Ductile iron has applications in the following areas:
- The automotive industry: It is used to make crankshafts, closures, hydraulic components, and parts of automobiles.
- In addition, it is used in railways and railroad trucks due to its ability to resist fatigue.
- Fluid power processes: Where it is used to make rod kits.
Additional Types of Iron
Other types of iron exist, they are:
4. Pig Iron
Pig iron is the direct product of blast furnaces. It is named pig iron because the molten iron is poured into molds that resemble piglets.
Pig iron is essential as an intermediary between iron and steel manufacturing. Should a company need to manufacture steel, pig iron can serve as a raw material. Pig iron also has applications in the chemical industry and construction.
5. Stainless Steel
Stainless steel consists of chromium and other metal alloy like nickel and molybdenum. It is characterized by high corrosion resistance which makes it durable and applicable in surgical instruments and kitchen appliances.
6. Tool Steels
Tool steels are alloy steels with a high level of hardness resulting from a highly fused metal lattice. They contain metal and carbon, along with other alloy components like chromium, vanadium, and tungsten. These steels are particularly known for their ability to withstand stress based on their hardness and resistance to deformation. They can also function at high temperatures without softening.
Tool steels are produced through tempering, a process that involves heating the steel between 200°C – 700°C, and then cooling it almost immediately at a rapid pace. Nickel and cobalt are responsible for tool steel ability to resist softening, even at high temperatures.
7. Alloy steels
Alloy steels are a sort of steel made up of different alloying metals added together with the motive of improving the quality of alloy steels. As such, alloy steels have some superior qualities compared to normal steels. The alloy metals are added to the alloy steel in specific ratios of components.
Apart from alloying metals and carbon, some other component elements are nickel, magnesium, vanadium, and chromium. These component elements give alloy metals superior mechanical properties targeted to meet specific project demands and industry needs.
8. Carbon steel
Carbon steel is a kind of steel composed of a major iron part, a significant carbon component, and smaller ratios of other alloying elements. Carbon steel has applications in diverse industries due to its low production cost and carbon-induced strength.
As a result of varying chemical components and mechanical features, carbon steels are classified into different grades. These grades are high-carbon steel, medium-carbon steel, low-carbon steel, and ultra-high-carbon steel. High to medium carbon steel has high levels of hardness and strength that inform their use in the production of machinery parts.
9. Pure Iron
Pure iron has a purity of up to about 99.85%, with tiny amounts of manganese, carbon, and other trace alloy elements. Due to its purity, it has widespread applications in different industries, resulting in excellent performance. Its applications are found in the automotive and aerospace industries, petroleum industries, construction, and the manufacture of magnets, lighting conductors, and fuse wires.
Some of its desirable features include high resistance to corrosion, outstanding magnetism, and welding suitability. However, pure iron is soft, and its inability to withstand certain extents of stress and compression creates a gap. Pure iron needs to be mixed with other alloy components to improve its hardness properties.
Contrast Table
| Cast Iron | Wrought Iron | Ductile Iron | |
|---|---|---|---|
| Use | Shaped into intricate designs with applications in machinery manufacture and cookware. | Mostly used for its aesthetic properties with application in decorative structures. | Has applications in the automotive industry, manufacture of machinery, and structural components. |
| Structure | Graphite components takes the form of flakes, distributed throughout the cast iron structure as the molten iron solidifies. | An alloy of iron, slag, and other elements. The presence of slag in its structure gives it a grainy appearance that becomes visible when stressed. | It has a spherical nodule structure. |
| Corrosion Resistance | Least corrosion resistance | Most corrosion resistance | Intermediate resistance to corrosion |
| Production | Involves molting and pouring cast iron into desired mold shapes. | Not poured into molds, but hammered, bent, and shaped into desired form through working. | Similar to cast iron’s production but with a nodulizing agent |
| Carbon content | About 2-4% | About 0.05%-0.25%. | About 3.2 to 3.6% |
| Labor-intensity | Less labor-intensive. | Labor-intensive, requires heating and hammering to impose its fibrous structure and eliminate impurities. | Less labor-intensity |
| Tensile Strength | Has a lower tensile strength compared to wrought iron. | Compared to cast iron, has more tensile strength. | Higher tensile strength compared to wrought iron and cast iron. |
| Softness and Ductility | harder and more brittle than wrought iron. | More ductile and softer than cast iron. | Superior ductility and softness in comparison to wrought iron and cast iron. |
Frequently Asked Questions:
Some of the most frequently asked questions include:
How are wrought iron, cast iron, and ductile iron produced?
Wrought iron is produced by continuously heating and working the iron, beating, bending, shaping, and puddling to remove impurities. Cast iron requires a different, less labor-intensive process, requiring molding the iron, adding alloys to the molten iron, and pouring the molten iron into a mold. Ductile iron has a similar production process to cast iron; however, it involves the addition of a nodulizing agent.
What is the most corrosion-resistant iron?
Because of its low carbon content, wrought iron is more resistant to corrosion than ductile iron and cast iron. The slag components prevent corrosion, and the fibrous structure aids this process by forming a protective interlock.
Is cast iron and wrought iron the same, and can they be used interchangeably?
You cannot interchangeably use cast iron and wrought iron because of their differences, which include a mix of their properties, applications, benefits, and disadvantages. Cast iron is better for processes requiring high compression, whereas wrought iron is used when structures need versatility.
Conclusion
There are numerous types of iron and these irons possess different properties, applications, and benefits. Wrought iron and cast iron are extensively used in manufacturing, and although ductile iron has a reduced manufacturing use, it possesses particular applications. Particularly where unique iron features are needed. By now, you should have a better understanding of the type of iron you need for your project. However, if you’re still uncertain or need expert assistance in selecting the right type of iron, Richconn is here to help. Our team of engineers is highly skilled in transforming complex designs into high-quality products. Contact us today to experience the best quality and service in the industry.
