2205 duplex stainless steel is a widely used duplex stainless steel
material, which has excellent comprehensive performance and is
widely used in various industrial fields. The following is a
detailed introduction to it in English:
Introduction to 2205 Duplex Stainless Steel
2205 duplex stainless steel, also known as UNS S31803 or S32205, is
a chromium-nickel-molybdenum duplex stainless steel. It gets its
name from its unique microstructure, which consists of
approximately 50% austenitic and 50% ferritic phases. This
dual-phase structure endows it with superior mechanical properties
and corrosion resistance compared to traditional austenitic or
ferritic stainless steels.
Chemical Composition
The typical chemical composition of 2205 duplex stainless steel (in
weight percentage) is as follows:
- Chromium (Cr): 21.0% - 23.0%
- Nickel (Ni): 4.5% - 6.5%
- Molybdenum (Mo): 2.5% - 3.5%
- Manganese (Mn): ≤2.0%
- Silicon (Si): ≤1.0%
- Carbon (C): ≤0.03%
- Nitrogen (N): 0.08% - 0.20%
- Phosphorus (P): ≤0.03%
- Sulfur (S): ≤0.02%
The balanced composition of chromium, nickel, molybdenum, and
nitrogen gives it excellent corrosion resistance and mechanical
strength.
Mechanical Properties
2205 duplex stainless steel has high strength and good ductility,
and its typical mechanical properties at room temperature are:
- Tensile strength: ≥620 MPa
- Yield strength (0.2% offset): ≥450 MPa
- Elongation at break: ≥25%
- Hardness (HB): ≤290
Compared with austenitic stainless steels (such as 304 or 316), it
has about twice the yield strength, which can reduce the thickness
of the material used and achieve the purpose of lightweight under
the same strength requirements.
Corrosion Resistance
- Pitting and Crevice Corrosion Resistance: Due to its high chromium,
molybdenum, and nitrogen content, 2205 duplex stainless steel has
excellent resistance to pitting and crevice corrosion. Its pitting
corrosion resistance equivalent number (PREN) is usually above 32
(calculated by the formula: PREN = %Cr + 3.3×%Mo + 16×%N), which is
much higher than that of 316L stainless steel.
- Stress Corrosion Cracking (SCC) Resistance: The dual-phase
structure makes it have better resistance to SCC in chloride
environments than austenitic stainless steels. It can be used in
environments where traditional austenitic stainless steels are
prone to SCC, such as seawater, brine, and chemical process fluids.
- General Corrosion Resistance: It also has good resistance to
general corrosion in many acidic and alkaline media, such as dilute
sulfuric acid, phosphoric acid, and various organic acids.
Fabrication and Welding
- Hot and Cold Working: 2205 duplex stainless steel can be hot-formed
or cold-formed, but cold working will increase its strength and
hardness and reduce its ductility. Appropriate annealing treatment
may be required after severe cold working to restore its ductility
and corrosion resistance.
- Welding: It can be welded by common welding methods, such as
tungsten inert gas welding (TIG), metal inert gas welding (MIG),
and shielded metal arc welding (SMAW). During welding, it is
necessary to pay attention to controlling the heat input to avoid
excessive grain growth and the formation of harmful phases, which
may affect its mechanical properties and corrosion resistance.
Post-weld heat treatment is usually not required, but rapid cooling
after welding is recommended to maintain the balance of the
dual-phase structure.
Applications
Due to its excellent properties, 2205 duplex stainless steel is
widely used in the following fields:
- Oil and Gas Industry: Used for offshore platforms, pipelines,
valves, pumps, and other equipment, which need to withstand the
corrosion of seawater and acidic media.
- Chemical and Petrochemical Industry: Applied to reactors, heat
exchangers, tanks, and pipelines for handling corrosive chemicals.
- Marine Engineering: Used in shipbuilding, seawater desalination
equipment, and marine structures.
- Paper and Pulp Industry: Used in equipment exposed to bleaching
agents and other corrosive substances.
- Construction and Architectural Applications: For decorative
components and structural parts in harsh environments.
- Power Generation: Used in power plant equipment, especially in
systems involving wet flue gas desulfurization.
Standards and Specifications
2205 duplex stainless steel complies with various international and
national standards, including:
- ASTM A240 / A240M
- EN 10088-2
- ASME SA-240
- ISO 683-13
These standards specify the chemical composition, mechanical
properties, and testing requirements of the material to ensure its
quality and consistency.
In summary, 2205 duplex stainless steel is a high-performance
engineering material. Its unique dual-phase structure makes it have
a perfect balance of strength, corrosion resistance, and
processability, making it an ideal choice for many demanding
industrial applications.
201 304 316L Anti Slip Checkered Stainless Steel Sheet
