EN GJS 400, also known as GGG40 or EN-GJS-400-15, is a type of ductile cast iron primarily composed of Carbon, Silicon, Manganese, Sulphur, and Phosphorus within specific ranges, carefully controlled to achieve its characteristic mechanical properties.
Detailed Chemical Composition of EN GJS 400
The precise chemical composition of EN GJS 400 is crucial for its performance as a ductile iron, particularly its excellent ductility and strength. The proportions of these elements directly influence the formation of graphite nodules, which are characteristic of ductile iron and impart its unique properties.
Here is the typical chemical composition of EN GJS 400:
| Element | Symbol | Content (%) |
|---|---|---|
| Carbon | C | 3.4 - 3.85 |
| Silicon | Si | 2.3 - 3.1 |
| Manganese | Mn | 0.1 - 0.3 |
| Sulphur | S | 0.02 max. |
| Phosphorus | P | 0.10 max. |
Understanding the Role of Key Elements in EN GJS 400
Each element in the composition plays a vital role in determining the final properties of EN GJS 400. Controlling these elements within the specified ranges ensures the material exhibits the desired balance of strength, ductility, and machinability.
- Carbon (C): As the primary alloying element, carbon is essential for the formation of graphite. In ductile iron, carbon precipitates as spherical nodules, which prevent crack propagation and contribute to the material's ductility. The specified range ensures adequate graphite formation without leading to excessive carbides or free carbon.
- Silicon (Si): Silicon acts as a powerful graphitizing agent, meaning it promotes the formation of graphite and aids in the development of the desired spherical graphite nodules. It also influences the matrix structure of the iron.
- Manganese (Mn): Manganese affects the matrix structure of the iron and can contribute to strength. However, its content is kept low in ductile iron because higher levels can lead to the formation of carbides, which reduce ductility and machinability.
- Sulphur (S): Sulphur is generally considered an undesirable element in ductile iron and must be kept to a very low maximum. High sulphur content can interfere with the nodularization process, leading to irregular graphite shapes and significantly reducing the material's mechanical properties.
- Phosphorus (P): Similar to sulphur, phosphorus is also detrimental to the mechanical properties of ductile iron, especially its impact strength and ductility, even at relatively low concentrations. Therefore, its content is strictly limited.
Properties and Applications of EN GJS 400
The carefully balanced chemical composition of EN GJS 400 results in a ductile iron grade known for its high tensile strength (minimum 400 N/mm²) and excellent elongation (minimum 15%). These properties make it suitable for a wide range of applications where good machinability, wear resistance, and the ability to absorb impact are required. Common uses include:
- Automotive components
- Agricultural machinery parts
- Valves and fittings
- Pipes and pipe fittings
- General engineering castings
For more detailed information on materials like EN GJS 400-15, you can refer to specialized material guides from manufacturers such as Gieterij Dijkkamp.
