Properties of CD4MCuN Duplex Stainless Steel

CD4MCuN is a duplex stainless steel that is commonly used in harsh environments, such as offshore oil and gas production, due to its superior corrosion resistance properties. This alloy is a modified version of CD4MCu, which also contains nitrogen for improved corrosion resistance. In this article, we will explore the properties of CD4MCuN in detail.

Equivalent steel grades of CD4MCuN: 

UNS S32750; UNS S32550; SAE 904L; SUS 904L; UNS N08904; EN 1.4539; SS2562

The chemical composition of CD4MCuN is as follows:

• Carbon (C): 0.030% max
• Silicon (Si): 1.00% max
• Manganese (Mn): 1.50% max
• Phosphorus (P): 0.040% max
• Sulfur (S): 0.030% max
• Chromium (Cr): 24.0-26.0%
• Nickel (Ni): 3.0-5.0%
• Molybdenum (Mo): 1.5-2.5%
• Copper (Cu): 1.5-3.0%
• Nitrogen (N): 0.20-0.35%

The addition of nitrogen in CD4MCuN improves its corrosion resistance properties compared to its predecessor CD4MCu. The high levels of chromium, molybdenum, and copper in CD4MCuN also contribute to its excellent corrosion resistance properties, while the low carbon content enhances its weldability

Corrosion Resistance:

One of the most significant properties of CD4MCuN is its exceptional corrosion resistance. This alloy offers superior resistance to pitting and crevice corrosion in chloride-containing environments, making it well-suited for use in offshore and marine environments. CD4MCuN also offers good resistance to general corrosion in a wide range of corrosive media.

Mechanical Properties:

Here are the mechanical properties of CD4MCuN:

• Tensile Strength: The tensile strength of CD4MCuN ranges from 550 to 700 MPa (80 to 101 ksi). Tensile strength is the maximum stress that a material can withstand before it fractures under tension.
• Yield Strength: The yield strength of CD4MCuN ranges from 350 to 450 MPa (51 to 65 ksi). Yield strength is the stress level at which a material begins to deform permanently.
• Elongation: The elongation of CD4MCuN is typically around 25%. Elongation is the amount of deformation that a material can undergo before it fractures.
• Hardness: The hardness of CD4MCuN is typically in the range of 25 to 30 HRC (Rockwell C). Hardness is a measure of a material's resistance to deformation or scratching.
• Fatigue Strength: The fatigue strength of CD4MCuN is also high, which means that it can withstand repeated loading and unloading cycles without suffering from fatigue failure.

The mechanical properties of CD4MCuN are largely unaffected by high temperatures, making it suitable for use in high-temperature environments. CD4MCuN is also highly weldable using conventional welding techniques, such as gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), and shielded metal arc welding (SMAW). However, due to its high strength and hardness, CD4MCuN can be more difficult to machine than some other stainless steels.

Weldability:

CD4MCuN is highly weldable using conventional welding techniques, such as gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), and shielded metal arc welding (SMAW). This alloy exhibits good weldability due to its low carbon content and high chromium and molybdenum content.

Heat Resistance:

CD4MCuN has excellent heat resistance properties, making it suitable for use in high-temperature environments. It has a maximum service temperature of 300°C (572°F), and its mechanical properties are largely unaffected at elevated temperatures.

Machinability:

CD4MCuN has good machinability, but it can be more difficult to machine than some other stainless steels due to its high strength and hardness. Carbide tools are recommended for machining CD4MCuN.

Applications:

CD4MCuN is commonly used in offshore and marine environments, such as in offshore oil and gas production facilities, seawater desalination plants, and marine equipment. It is also used in chemical processing, pulp and paper production, and other corrosive environments where superior corrosion resistance is required.

In conclusion, CD4MCuN is a duplex stainless steel alloy with excellent corrosion resistance, mechanical properties, weldability, heat resistance, and machinability. Its unique combination of properties makes it well-suited for use in harsh environments where other alloys may fail. Understanding the properties of CD4MCuN can help engineers and designers select the appropriate material for their specific application, ensuring optimal performance and reliability.