Iron casting, one of the oldest and most recognized casting methods, is melted and poured into molds or casts to creat a part of products of desired dimensions and shape. They are allowed to cool down and solidfy before being removed from the molds and used. Iron castings can be used in a variety of industries and employed for an array of uses.
Cast iron is an alloy of iron, carbon and silicon with carbon levels of about 3.2% and silicon at about 2.2%. Compared with steel casting, iron casting has a wide range of advantages of few less lucrative properties. We can divide cast iron into grey cast iron, ductile cast iron and malleable cast iron. The difference in these types of iron is the characteristics of the graphite used in the material.
Grey Iron Casting: Grey iron is called that because when it is fractured, its surface appears a dull grey color. It has good casting properties, high machinability, good wear resistance as well as good vibration damping. It can withstand greater load and has a good degree of resistance against corrosion. It, however, has low tensile strength and elongation properties. It is often used to manufacture parts like cylinder blocks, pistons, gear boxes, knives, table wheels, pipes, valves, etc.
Ductile Iron Casting: In Ductile iron, the graphite is like a pillow and acts as “crack-arresters” to give ductility and toughness superior to all other cast irons. They have high strength, high heat-resistance and toughness. They are used in a wide range of industries: engineering, agriculture, automotive, road and construction, etc. The production of ductile iron casting is more complex and expensive than grey cast iron. They may also have more casting defects than grey iron casting.
Common Used Material Standards in Iron Casting:
| Cast Iron | Standards | |||||
| GB | AWS | BS | NF | DIN | ISO | |
| Grey Iron | HT200 | No.30 | Grade 220 | EN-GJL-200 | GG20 | 200 |
| HT250 | No.35 | Grade 260 | EN-GJL-250 | GG25 | 250 | |
| HT300 | No.45 | Grade 300 | EN-GJL-300 | GG30 | 300 | |
| HT350 | No.50 | Grade 350 | EN-GJL-350 | GG35 | 350 | |
| Ductile Iron | QT450-10 | 65-45-12 | GGG-40 | EN-GJS-450-10 | 450/10 | 450-10 |
| QT450-18 | 60-40-18 | GGG-40 | EN-GJS-450-18 | 400/18 | 450-18 | |
| QT500-7 | 80-55-06 | GGG-50 | EN-GJS-500-7 | 500/7 | 500-7 | |
Iron Casting Process
Like steel casting, there are also different kind of methods of producing iron castings. Simply speaking, iron castings could be customized in sand casting or lost foam casting technics.
Sand Casting: Also called sand molded casting. Is the process that utilizes non-reusable sand molds to form metal castings. Sand casting is used to produce a wide variety of cast iron components with complex geometries. In China, there are three types of sand casting techniques to make iron castings. They are precoated sand casting, resin sand casting and clay sand casting. Among them, precoated sand casting is the most precision sand casting process with general casting tolerance CT8. It is able to produce iron castings less than 2kgs. Clay sand casting is the second precision casting process with general casting tolerance CT9. Iron castings between 2kgs-60kgs are availble in this method. And resin sand casting is mainly used for the production of large iron castings above 60kgs.
Lost Foam Casting: Lost foam casting is another casting technique for iron castings. It is a type of evaporative-pattern casting process that is similar to investment casting. But replace the wax with foam for the pattern. The advantages of lost foam casting is that the boiling point of foam is low, this helps to simplify the investment casting process by removing the need to melt the wax out of the mold. Cast iron is one of the commonly cast material in lost foam casting process. With lost foam casting, we can make small iron castings in good dimensional accuracy and surface finish. For large iron castings, sand casting is preferred.
Advantages of Iron Casting over Steel Casting
Strength: Both steel and iron have high strength. By comparision, iron casting typically has a better compressive strength than steel casting.
Cost: While the cost for steel castings are initially more expensive than iron castings, they can end up being a more cost effective option when you consider long-term use and replacement costs.
The disadvantages of Iron casting is that it has a better corrosion resistance than steel casting. That is to say, both metals will oxidize and begin to fade away in the presence of moisture. As a result, steel is actually a better option when seeking corrosion resistance because they are better at preventing oxidation.
Iron Casting from China Company
TCC Iron Casting Company has a long history of iron casting production in China, we continue to upgrade our equipment and plant facilities in order to provide our customers with the highest quality products using the latest lost foam casting and sand casting technology. Our modern furnaces can help to reduce production times with faster melting, and enhance our ability to provide competitively priced high quality iron castings. Our knowledgeable and experienced team provides in-house heat-treating and metallurgical testing to ensure timely production of your order. Below are the pictures of some iron castings we made. Give us an email or call for your needs of custom iron castings.