2205 duplex stainless steel pipes are (austenite-ferrite) duplex stainless steel (2205 duplex steel for short) composed of 22% chromium, 3% molybdenum, and 4.5% nickel-nitrogen alloy. 2205 duplex stainless steel pipes are nitrogen-added duplex stainless steel pipes with high strength, good impact toughness, and good overall and local stress corrosion resistance. 2205 duplex steel is particularly suitable for temperatures within the range of -50°F/+600°F. This alloy can also be considered for applications beyond this temperature range.

The main feature of 2205 duplex stainless steel pipes is that the yield strength can reach 400-550MPa, which is twice that of ordinary austenitic stainless steel. This feature allows designers to reduce weight when designing products, so they can save materials. This alloy has a price advantage over 316 and 317L, reducing equipment manufacturing costs. In terms of corrosion resistance, especially in harsh media environments (such as seawater, and high chloride ion content), the pitting, crevice corrosion, stress corrosion, and corrosion fatigue resistance of duplex stainless steel are significantly better than those of ordinary austenitic stainless steel and can be comparable to high-alloy austenitic stainless steel.

Due to the special performance characteristics of 2205 duplex steel pipes, the product types include bars, wires, welded pipes, seamless pipes, steel plates, forgings, strips, etc., with a wide range of applications. It is still the most widely used grade in duplex steel.

First, the physical and mechanical properties of 2205 duplex stainless steel pipes
Density: 8.0g/cm3.
Tensile strength: σb≥620Mpa.
Yield strength: σ0.2≥450Mpa
Elongation: δ≥25%.

Second, the corrosion resistance of 2205 duplex stainless steel pipe
1. Uniform corrosion: Due to the chromium content (22%), molybdenum (3%), and nitrogen content (0.18%) of 2205 duplex steel pipe, the corrosion resistance of 2205 is better than 316L and 317L in most environments.
2. Local corrosion resistance: The content of chromium, molybdenum, and nitrogen in 2205 duplex steel pipe makes it highly resistant to pitting corrosion and crevice corrosion in oxidizing and acidic solutions.
3. Stress corrosion resistance: The duplex microstructure of 2205 duplex steel pipe helps to improve the resistance of stainless steel to stress corrosion cracking. Under certain temperature, stress, oxygen and chloride, austenitic stainless steel will undergo chloride stress corrosion. Because these conditions are not easy to control, the use of 304L, 316L and 317L is limited in this regard.
4. Corrosion fatigue resistance: The high strength and corrosion resistance of 2205 duplex steel pipe make it have high corrosion fatigue strength. Processing equipment is susceptible to corrosive environments and loading cycles, and the characteristics of 2205 stainless steel pipes are very suitable for such applications.

Third, the structure of 2205 duplex stainless steel pipes
The chemical composition of 2205 duplex steel pipes can obtain an ideal microstructure of 50 α / 50 γ after solution annealing at 1900°/1922°F (1040°/1080°C).

Fourth, the application field of 2205 duplex stainless steel pipes
2205 duplex steel pipe application fields: neutral chloride environment, oil refining industry, petrochemical and chemical industry, chemical industry pipelines, oil and gas industry, pulp and paper industry, fertilizer industry, urea industry, phosphate fertilizer industry, seawater environment, energy and environmental protection industry, light industry and food industry, food and pharmaceutical industry equipment, high-strength structural parts, submarine pipelines, smoke machine desulfurization, osmotic desalination equipment, sulfuric acid plants, marine engineering fasteners, etc. As a special steel, 2205 is superior to ordinary stainless steel in both hardness and performance.