Cast Iron vs. Ductile Iron Flange Adapters: Which is Better?

Feb 21, 2024 | NEWS

Flange adapters play a crucial role in connecting pipes and components with different flange types or sizes. They are commonly manufactured from various materials, including cast iron and ductile iron. This article aims to compare cast iron and ductile iron pipe flange adapter, highlighting their key differences and suitability for various applications.

Cast Iron Flange Adapters:

Material Composition:

Cast iron flange adapters are made from molten iron poured into a mold and allowed to solidify.

They contain a high carbon content, making them relatively brittle and susceptible to cracking under stress.

Strength and Durability:

Cast iron flange adapter have lower tensile strength compared to ductile iron adapters.

They are more prone to breakage and may not withstand high pressure or extreme temperature fluctuations.

Corrosion Resistance:

Cast iron flange adapters are susceptible to corrosion, especially in environments with high moisture or exposure to chemicals.

Regular maintenance and protective coatings are necessary to prevent rust and extend their lifespan.

Ductile Iron Flange Adapters:

Material Composition:

Ductile iron flange adapters are made from a modified form of cast iron that undergoes a special heat treatment process.

This process reduces the carbon content and increases the amount of graphite, resulting in a stronger and more ductile material.

Strength and Durability:

Ductile iron flange adapters possess higher tensile strength and ductility compared to cast iron adapters.

They are more resistant to cracking and can withstand higher pressure and temperature variations.

Corrosion Resistance:

Ductile iron flange adapters have improved corrosion resistance compared to cast iron.

They are less prone to rust and can endure harsh environments, making them suitable for outdoor or underground applications.


FeatureCast Iron Flange AdaptersDuctile Iron Flange Adapters
Material CompositionHigh carbon content, brittleModified cast iron, ductile
Strength and DurabilityLower tensile strength, prone to breakageHigher tensile strength, more durable
Corrosion ResistanceSusceptible to corrosionImproved corrosion resistance
ApplicationsLow-pressure systems, indoor useHigh-pressure systems, outdoor or underground use

Cast iron and ductile iron flange adapters serve different purposes based on their material properties and characteristics. Cast iron adapters are suitable for low-pressure systems and indoor applications where corrosion is not a major concern. Ductile iron adapters, with their superior strength and corrosion resistance, are ideal for high-pressure systems, outdoor installations, and environments with harsh conditions. By understanding the differences between these two materials, engineers, plumbers, and contractors can select the appropriate flange adapters to ensure reliable and long-lasting connections in their piping systems.