GGG-40 material is equivalent to ductile iron, belonging to the German DIN standard grade. Its corresponding Chinese grade is QT400-15.
Material Characteristics and Standards
Composition and Structure: GGG40 is mainly composed of iron, carbon, and silicon, with graphite existing in a spherical form, exhibiting good strength and toughness.
Mechanical Properties: As ductile iron, its tensile strength is approximately 400 MPa, and its elongation is approximately 15%, making it suitable for applications requiring high strength and plasticity, such as valves and mechanical parts.
International Comparison: Besides the Chinese QT400-15, GGG40 also corresponds to similar grades in other standards (such as Japanese FCD400, American 60-40-18, etc.), but specific performance parameters should be based on the actual standard.
How is the corrosion resistance of GGG40?
GGG40 is a type of ductile iron, and its corrosion resistance is as follows:
Basic Corrosion Resistance
Non-Severe Corrosion Environments: In ordinary urban water supply and drainage environments, it can resist the corrosion of dissolved oxygen and trace amounts of acidic and alkaline substances in water.
Severe Corrosion Environments: In environments with strong acids, strong alkalis, or containing large amounts of corrosive ions (such as chloride ions), its corrosion resistance is weaker.
Methods to Enhance Corrosion Resistance
Surface Treatment: Corrosion resistance can be significantly improved through painting, galvanizing, etc. For example, in wastewater containing sulfides, ductile iron valves treated with anti-corrosion agents can be used for a long time.
Alloying Elements: Adding elements such as copper can form a dense oxide film (such as CuO, Cu₂O), slowing down the corrosion process and synergistically enhancing corrosion resistance with other elements (such as nickel, chromium).
Comparison with Other Materials
Superior to Gray Cast Iron: The spheroidal graphite structure reduces stress concentration, resulting in superior corrosion resistance compared to ordinary gray cast iron.
Less than Carbon Steel: Carbon steel valves are generally more durable in highly corrosive environments.
Application Recommendations: Suitable for low to medium pressure, non-corrosive piping systems (such as water supply and drainage). For use in corrosive environments, surface treatment or alloying products are required.
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