CD3MN(SS2205)Duplex Stainless Steel

Table of Contents

CD3MN duplex stainless-steel overview

CD3MN (ASTM A 890 4A) duplex stainless steel is an alloy that is composed of approximately 22% chromium, 5% nickel, and 3% molybdenum. Its name is derived from its microstructure, which consists of a balanced mixture of ferrite and austenite, known as a duplex structure.


This duplex stainless steel offers excellent corrosion resistance in a wide range of environments, including seawater, acid, and chloride-containing environments. It is also highly resistant to pitting and crevice corrosion, making it a popular choice in oil and gas, chemical, and marine industries.


In addition to its corrosion resistance, CD3MN duplex stainless steel also offers high strength and toughness, along with good weldability and machinability. These properties make it a versatile material that can be used in a variety of applications, including pressure vessels, piping systems, and structural components.


CD3MN is also named SS2205 in the market, which is probably the most recognized and widely used of the many duplex stainless steels. SS2205 is used in the pump industry, such as pump casing and pump impeller. And CD3MN won’t pit like regular stainless steel, has a better stress/corrosive cracking resistance than standard stainless, and has higher strength than standard stainless steel. And compared with regular cast iron material, it is much more resistant to corrosion and much stronger.


Overall, CD3MN duplex stainless steel is a reliable and cost-effective material that offers excellent corrosion resistance, strength, and toughness for a range of applications in harsh environments.

Advantages and disadvantages of CD3MN (SS2205)

CD3MN (SS2205) duplex stainless steel offers several advantages and disadvantages, which are important to consider when selecting this material for specific applications. Let’s explore them in detail:


  • Corrosion Resistance: CD3MN exhibits excellent resistance to corrosion, especially in environments containing chlorides, making it suitable for applications in marine and chemical industries.
  • High Strength: This alloy possesses high tensile and yield strength, providing structural integrity and durability to components subjected to heavy loads and stress.
  • Good Weldability: CD3MN demonstrates good weldability, allowing for easy fabrication and assembly of complex structures.
  • Cost-Effective: Compared to other corrosion-resistant alloys, CD3MN offers a cost-effective solution without compromising on performance and durability.
  • Good Toughness: The balanced microstructure of ferrite and austenite in CD3MN imparts good toughness, enabling it to withstand impact and shock loading.
  • Versatility: CD3MN finds applications in a wide range of industries, including oil and gas, chemical processing, marine, and pulp and paper, due to its versatile properties.
  • A890/A995 4A (CD3MN) has good casting performance and is suitable for centrifugally cast duplex


  • Embrittlement at High Temperatures: CD3MN may undergo embrittlement and loss of toughness when exposed to temperatures exceeding 300°C (572°F). Care should be taken to avoid such operating conditions.
  • Reduced Toughness in Certain Environments: While CD3MN generally exhibits good toughness, it may experience reduced toughness in environments with high hydrogen sulfide (H2S) concentrations or low pH levels.
  • Complex Microstructure: The dual-phase microstructure of CD3MN requires careful control during heat treatment and welding processes to maintain optimal mechanical properties.
  • Limited Use at Extreme Temperatures: CD3MN is not recommended for use in applications where the operating temperatures consistently exceed its upper-temperature limit of approximately 300°C (572°F).
  • Sensitivity to Chemical Composition: The performance of CD3MN is sensitive to its chemical composition, requiring strict control during manufacturing to ensure desired properties.
  • Understanding the advantages and disadvantages of CD3MN (SS2205) allows engineers and designers to make informed decisions regarding material selection, ensuring optimal performance and longevity of components in specific applications.

cd3mn properties chemical composition

Carbon:                                                                  0.03% Max

Manganese:                                                          1.50% Max

Silicon:                                                                   1.00% Max

Phosphorus:                                                          0.04% Max

Sulfur:                                                                     0.02% Max

Chromium:                                                        21.00-23.00%

Nickel:                                                                  4.50 – 6.50%

Molybdenum:                                                     2.50 – 3.50%

Nitrogen:                                                             0.15 – 0.25%

Copper:                                                               1.00% Max

cd3mn/DSS2205 duplex stainless steel impeller
cd3mn/DSS2205 duplex stainless steel impeller

CD3MN Physical properties

  • Yield Strength:                        60 ksi Min
  • Tensile Strength:                    90 ksi
  • Elongation at 2 in:                  25% Min

Casting Material Standard:

Casting Material Grades cd3mn equivalent

  • Cast Alloy Designation: CD3MN.
  • Similar designation: DUPLEX 4A, 2205.
  • UNS #: J92205.
  • ASTM Standard(s): A890/A995.
  • Wrought: CD3MN.
  • ASTM A890/A995 Grade 4A;
  • Type 22Cr-5Ni-Mo-N;
  • Casting UNS J92205;
  • ACI CD3MN;
  • Wrought UNS S31803;
  • Wrought grade SS2205;
  • W.Nr EN 1.4462;
  • X2CrNiMoN22-5-3;
  • SUS 329J3.
  • ASTM 182 F51; F60
  • UNS 32205

CD3MN (SS2205) Casting Typical Application

  • CD3MN (SS2205) casting is duplex stainless steel that contains a balanced mix of ferrite and austenite, with a high level of chromium and molybdenum. This material is commonly used in applications where high strength, corrosion resistance, and good weldability are required. Some typical applications of CD3MN (SS2205) casting include:


    • Chemical processing equipment: CD3MN (SS2205) is commonly used in the construction of chemical tanks, pipelines, and pumps due to its excellent resistance to corrosive and acidic environments.


    • Oil and gas industry: This material is ideal for use in offshore drilling platforms, subsea pipelines, and other equipment that is exposed to high levels of saltwater and other corrosive substances.


    • Food and beverage processing: CD3MN (SS2205) is often used to construct conveyors, tanks, and other equipment that meets food and beverages due to its resistance to corrosion and pitting.


    • Marine industry: This material is frequently used in the construction of boats, ships, and other marine vessels due to its strength and resistance to seawater.


    • Automotive industry: CD3MN (SS2205) is commonly used in the manufacturing of exhaust systems, turbochargers, and other engine components due to its high strength and corrosion resistance.

    In general, the use of CD3MN (SS2205) casting is an outstanding option when there is a need for durability, corrosion resistance, and ease of welding.

CD3MN (SS2205) Casting Heat treatment process:

CD3MN (SS2205) is a duplex stainless steel. Here is the heat treatment process for CD3MN (SS2205) castings:

Solution Treatment:

  1. Heat the CD3MN (SS2205) casting to a temperature of approximately 1950°F (1065°C) and hold it for a sufficient time to ensure uniform heating.
  2. Maintain the casting at the solution temperature for a specific duration, typically ranging from 30 minutes to 2 hours.
  3. The purpose is to dissolve carbides and precipitates in the casting, forming a homogeneous austenitic crystal structure.


  1. After the solution treatment, rapidly cool the casting to room temperature.
  2. Various rapid cooling methods can be employed, such as air cooling or water quenching.

It’s important to note that the specific heat treatment parameters for CD3MN (SS2205) castings may vary depending on the specific application and requirements. Therefore, in practical operations, designing the heat treatment process and selecting parameters based on relevant standards and expert advice is recommended.