How Is Ductile Iron Made? 5 Critical Steps of Ductile Iron Production

Ductile iron is an important engineering material used in different industries. It is versatile, sustainable, durable, strong, and resistant to wear and corrosion. If you want to take advantage of ductile iron, you should understand how it is made. There are five essential steps to create high-quality ductile iron. Selecting raw materials, melting, casting and solidification, heat treatment, and quality control are these five steps. Ductile iron is utilized in a broad range of industries, such as water and sewer systems, construction, engineering, etc. Keep reading this blog to learn more about this amazing material!

What Is a Ductile Iron?

First of all, you need to understand the basics of ductile iron. It’s also known as ductile cast, nodular, or graphite iron. That’s because ductile iron has a spherical graphite design. According to General Kinematics, this product was patented in 1948 for the first time, and since that day, different industries have used ductile cast iron as an engineering material. The presence of spherical graphite pieces in ductile iron provides it with some unique specifications. It offers many different advantages and is highly resistant to impact, wear, and tear. This material is vital in many ways. Different industries consider ductile iron as a necessary component to enhance their projects. Ductile iron applications cover a broad range. That’s why learning about this material is essential.

How Is Ductile Iron Made?

As explained, nodular iron is a valuable material for various industries. Yet, the process of making ductile iron is challenging and requires specific levels of expertise, knowledge, technology, etc. Here are five ductile iron production steps that all professionals follow.

Selection of Raw Materials

The first step in the ductile iron manufacturing process is to choose the right raw materials. This combination is important and can significantly impact the results. Professionals gather all key elements to ensure the quality of the outcome. Generally speaking, there are four critical raw materials used to produce ductile iron.

• Pig Iron: It’s obvious that pig iron is the primary material used to manufacture ductile iron. Typically, pig iron isn’t pure, and it contains silicon, carbon, and even manganese in small amounts. The presence of carbon in the combination of pig iron makes it easy to melt and become a useful alloy.
• Alloy Components: Many different alloy elements are used in this process. Chromium, manganese, nickel, and copper are some of these crucial elements. Each alloy has its own specifications, which is why ductile iron is beneficial in many different ways. The quality and quantity of chosen alloys can determine the final properties of ductile iron.
• Scrap Iron: Scrap iron and steel are two of the most important raw materials. Recycling these materials can help the environment and also strengthen ductile iron.
• Magnesium: It may be surprising to understand how magnesium is essential in spheroidal graphite iron manufacturing. It’s available in different forms of alloy and creates those important graphite nodules. Magnesium provides ductile iron with unique features that make it superior to its alternatives.

Melting and Treatment

The second stage of ductile iron production is about melting and treatment. After choosing the efficient raw materials, it’s time to load them into a furnace. These materials get exposed to high temperatures between 2600°F and 2800°F to get perfectly melted. Professionals need to control the temperature carefully during the melting process to prevent any potential issues. Low temperatures can make the final product inconsistent. On the other hand, high temperatures can burn some alloy elements and waste large amounts of energy. That’s why an expert should monitor the temperature all the time while the materials are getting melted. Afterward, they add magnesium to the molten ductile iron. After some reactions, they form graphite nodules. Magnesium can be added to the melted mixture in different ways. Tundish and sandwiching are two common techniques to complete this step.

Casting and Solidification

The third step includes casting and solidification. Professionals at McWane Ductile explain how they shape the melted ductile iron and allow it to cool down. Depending on the overall condition, many different casting methods are used. Here are four main approaches to casting ductile iron.

1. Centrifugal Casting: As the name suggests, this type of ductile iron casting uses centrifugal force to distribute the melted iron into a specific mold. This approach is a good option when you want to manufacture symmetrical or cylindrical shapes.
2. Sand Casting: It is the most common method of ductile iron casting. In this method, the mold is made from compacted sand and can have different shapes and forms. The melted iron is poured into this mold in the safest and most secure way possible. It’s also easy to remove any solidified iron during this process.
3. Lost Foam Casting: First, you need to create a foam pattern of your ductile iron shape. This form of pattern is surrounded by compacted foam. Finally, the foam pattern is vaporized as soon as the melted iron is poured into the mold.
4. Permanent Mold Casting: Professionals use metal molds that can be reused in the future. It’s also known as gravity casting and is suitable when you want to produce complex ductile iron shapes in high amounts.

Choosing the right approach to ductile iron casting is crucial. It can affect the quality and accuracy of the final outcome.

After casting, it’s time to start the solidification process. This is the stage when graphite nodules start to form by gradually reducing the temperature. As explained, these graphite nodules have a spherical shape due to the magnesium and other alloy elements. The contraction of the metal matrix around these nodules completes the process and provides ductile iron with unique specifications.

Heat Treatment

Although the product is usable at this stage, there is an additional step. This step is heat treatment, which can enhance the features and specifications of ductile iron. Different heat treatment processes can manipulate the details of ductile iron structures for more professional functions.

• Annealing: The internal stress in ductile iron can cause minor problems in projects. To prevent this condition, experts use the annealing technique. It means heating the ductile cast iron more than required. After reaching the temperature above the needed range, it’s time to cook the ductile iron down. This process makes the final product more flexible and improves its technical features.
• Normalizing: Specialists use this heat treatment process to improve the ductile iron properties. Just like annealing, the temperature should reach above the needed range, but the cooling process is quicker and done in still air.

Precise temperature control is essential in both procedures. These can improve the quality of the final product and make it more beneficial for different needs.

Control and Inception

The final step in making ductile iron is to control its quality. It should be done carefully to ensure the durability of the final product. Ductile iron is used in different industries and plays an important role in various places. That’s why it should meet important standards and offer guaranteed performance. Our professionals at Yasmin Trading run a lot of examinations, such as tensile, compression, and impact tests, to ensure quality. We are the leading supplier of Ductile Iron Pipe across the Middle East and Africa. You can consult our experts for further information!

What Are the Benefits of Ductile Cast Iron?

The casting process makes ductile iron superior to its alternatives. Here are some benefits that make this product an excellent option.

• Wear resistance
• Durability
• Sustainability
• Cost efficiency
• High strength
• Versatility
• Corrosion resistance

What Are the Common Applications of Ductile Iron?

After explaining how ductile iron is made, it’s time to understand its main applications. Due to its amazing properties, ductile iron is the first choice of many professionals in different industries. It is used in water infrastructure, construction, energy engineering, sewer systems, automation, and other industrial projects.

Final Thoughts

As explained, ductile iron is made through five challenging steps. From choosing raw materials to precise control, all these steps require expertise and technology. You can visit our experts to gain more information!