A ductile iron valve is a type of valve made primarily of ductile iron (also known as spheroidal graphite cast iron).
Ductile iron is produced by adding magnesium or rare earth elements to molten cast iron, causing graphite to precipitate in spherical shapes, thus significantly improving the material’s strength, toughness, and impact resistance.
Key Characteristics:
High Strength: Tensile strength can reach 450–600 MPa, superior to ordinary gray cast iron (such as HT200–300).
High Toughness: Impact energy ≥15 J at -20℃ (such as QT450-10), not easily brittle.
Good Wear Resistance and Vibration Damping: Suitable for applications with high vibration (such as water pump outlets).
Moderate Cost: More economical than stainless steel, yet superior in performance to ordinary cast iron.
Common Types and Applications
Ductile iron can be used in various valve structures, mainly including:
Butterfly Valves: Suitable for medium and low pressure systems such as water treatment, HVAC, and agriculture. Nominal pressure is typically PN0.6–4.0 MPa, and nominal diameter is DN50–1200.
Knife Gate Valves: Specifically designed for large-diameter, low-pressure (PN≤1.6 MPa) media containing slight particulate matter (such as sewage and slurry).
Gate Valves: Used for non-corrosive media such as water, oil, and gas. Operating temperature is generally -5℃ to 150℃, and pressure is 6–16 Bar.
Gate Valves: Some designs use ductile iron valve bodies, featuring flat-bottomed flow channels and resistance to sludge buildup.
Typical Material Grades [ASTM A536]
60-40-18: Excellent toughness, suitable for vibration environments.
65-45-12: High strength, suitable for high pressure differential scenarios.
80-55-06: For harsh operating conditions.
Applicable Media and Limitations
Applicable Media: Water, air, natural gas, oil, sewage, and other non-corrosive fluids.
Not Applicable: Strong acids, strong alkalis, high chloride ion concentrations, or extreme conditions such as high temperature and pressure (e.g., >4.0 MPa or >350℃). In these cases, stainless steel or alloy steel valves should be selected.
This is a brief introduction to ductile iron valves. If you have large-scale custom cast iron valve needs, you can choose to cooperate with Mulan Manufacturing Group. Mulan Manufacturing Group has 13 years of experience in cast iron casting and processing, and has helped customers in more than 30 countries complete the production and processing of various cast iron parts, receiving consistent recognition. We look forward to your cooperation inquiries.
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