Duplex stainless steel 2205 alloy is composed of 21% chromium, 2.5% molybdenum and 4.5% nickel nitrogen alloy consisting of duplex stainless steel. It has high strength, good impact toughness and good overall and local resistance to stress corrosion.
What’s more,2205 duplex stainless steel tube is a new product developed successfully in 2000, and the 2205 duplex stainless steel is a kind of duplex stainless steel with nitrogen (referred to as the dual phase steel of 2205).
2507 is a ferritic austenitic (duplex) stainless steel with excellent resistance to spot corrosion, crevice corrosion and uniform corrosion,with better mechanical property than 2205 duplex.
Production Standards
|
Grade
|
GB
|
ASTM
|
DIN
|
JIS
|
|
2205
|
022Cr23Ni5Mo3
|
S32205/S31803
|
W.Nr 1.4462
|
G4305
|
|
2507
|
25Cr-7Ni-4Mo-0.27N
|
UNS S32750
|
1.4410
|
--
|
Chemical Composition
|
Grade
|
C(%)
|
Si(%)
|
Mn(%)
|
P(%）
|
S(%)
|
Cr(%)
|
Ni(%)
|
N(%)
|
Mo(%)
|
|
2205
|
≤0.03
|
≤1.0
|
≤2.0
|
≤0.03
|
≤0.02
|
22.0-23.0
|
≤4.5-6.5
|
0.14-0.20
|
3.0-3.50
|
|
2507
|
≤0.03
|
≤0.8
|
≤1.2
|
≤0.035
|
≤0.02
|
24.0-26.0
|
≤6-8
|
0.24-0.32
|
3.0-3.50
|
Mechanical properties
|
Grade
|
TS
Mpa
|
YS
Mpa
|
EL
(%)
|
Rate of reduction in area
(%)
|
Density
(g/cm3)
|
|
2205
|
≥620
|
≥205
|
≥25
|
≥50
|
8.24
|
|
2507
|
800-1000
|
≥550
|
≥25
|
--
|
8.24
|
Specifications
|
Available technical
|
Available thickness
(mm)
|
Available width
(mm)
|
Available finish
|
Available origin
|
|
Cold rolled
|
0.5-3.0
|
Standard:1219mm 1500mm
Special :can be ordered
|
2B / No.4 / HL / BA / Mirror / Checkered / Colored etc
|
TISCO / JISCO etc
|
|
Hot rolled
|
3.0-100
|
Standard:1500mm 1800mm 2000mm
Special :can be ordered
|
No.1 / No.4 / HL / Mirror etc
|
TISCO / JISCO etc
|
Applications
1、Because 2205 stainless steel has high strength, good impact toughness and good overall and local stress corrosion resistance, and the yield strength of 2205 duplex stainless steel is austenitic stainless steel two times, this feature enables designers to design products lose weight, make this alloy has more than 316 317L price advantage. This alloy is particularly suitable for the temperature range of -50 DEG F/+600 DEG F. The alloy may be considered for applications beyond this temperature range, but there are some limitations, especially when applied to welded structures.
So,2205 stainless steel is widely used in our daily life such as:
1) Pressure vessels, high pressure storage tanks, high pressure pipelines, heat exchangers (chemical processing industry).
2) Oil and gas pipelines, heat exchanger tubes.
3) Sewage treatment system.
4) Pulp and paper industry classification, bleaching equipment, storage processing system.
4) High strength and corrosion resistance of the rotary shaft, press roller, blade, impeller, etc..
5) Cargo boxes for ships or trucks
6) Food processing equipment
2、2507 is a ferritic austenitic (duplex) stainless steel, which combines the most beneficial properties of many ferritic and austenitic steels. Because the content of chromium and molybdenum in this steel is very high, it has excellent resistance to spot corrosion, crevice corrosion and uniform corrosion The dual phase microstructure ensures that the steel has high resistance to stress corrosion cracking and high mechanical strength
2507 stainless steel is used as follows:
- oil and natural gas industry;
- Offshore stone sky shatter oil platform (heat ex changer pipe, water treatment and water supply system, fire protection system, water spraying system, water stabilization system;
- petrochemical equipment;
- desalination (desalination) equipment (and high-pressure pipe and seawater pipe in the equipment);
- Mechanical and structural components with high strength and corrosion resistance are required;
- Fuel (waste) gas purification equipment
More about for 2205 and 2507
Advantage for 2205 duplex
1) 2205 compared with 316L alloy and 317L austenitic stainless steel, duplex stainless steel, the performance of 2205 alloy in resistance to pitting corrosion and crevice corrosion of more superior, it has high corrosion resistance, and austenite than its lower thermal expansion coefficient, high thermal conductivity.
2) Dual phase stainless steel 2205 alloy and austenitic stainless steel, its compressive strength is two times, compared with 316L and 317L, designers can reduce its weight. 2205 alloy is particularly applicable to the temperature range of - 50 degrees F/+600 degrees F, in the case of strictly limited (especially for the welding structure), can also be used for lower temperature.
Corrosion resistance for 2205 duplex stainless steel
1) Uniform corrosion
Due to chromium content (22%), molybdenum (3%) and nitrogen content (0.18%), the corrosion resistance of 2205 in most environments is better than 316L and 317L.
2) Local corrosion resistance
The content of chromium, molybdenum and nitrogen in the dual phase steel 2205 has strong resistance to pitting corrosion and crevice corrosion in the oxidizing and acidic solution.
3) Resistance to stress corrosion
Dual phase microstructure of stainless steel is helpful to improve the resistance of the stainless steel stress corrosion cracking ability. In the presence of a certain temperature, stress, oxygen and chloride, the austenitic stainless steel will be a chloride stress corrosion. Because these conditions are not easy to control, so the use of 304L, 316L and 317L in this area is limited.
4) Corrosion fatigue
The high strength and corrosion resistance of dual phase steel 2205 have high corrosion resistance. The processing equipment is easy to be affected by the corrosion environment and the load cycle, and the characteristics of the 2205 are very suitable for this application.
Better mechanical property for 2507
1. Corrosion resistance
The high chromium and molybdenum content of SAF 2507 makes it have a strong overall corrosion resistance to organic acids such as formic acid and acetic acid SAF2507 alloy also has strong corrosion resistance to inorganic acids, especially those containing chlorides
Compared with 904L, SAF2507 has stronger corrosion resistance to diluted sulfuric acid mixed with chloride ion. 904L is an alloy in austenitic state and is specially used to resist pure sulfuric acid corrosion
Grade 316L cannot be used in hydrochloric acid environment, it may suffer local corrosion or overall corrosion. SAF2507 can be used in diluted hydrochloric acid environment, with strong resistance to spot damage and crack corrosion
2. Inter granular corrosion
The low carbon content of SAF 2507 greatly reduces the risk of carbide precipitation in the intergranular during heat treatment. Therefore, this alloy has strong resistance to intergranular corrosion related to carbides
3. Stress corrosion cracking
The compound structure of SAF 2507 makes it have strong resistance to stress corrosion cracking. Because of its high alloy content, the corrosion resistance and strength of SAF 2507 are better than 2205
Cracks are almost inevitable in construction, which makes stainless steel more vulnerable to corrosion in chloride environment SAF 2507 has a strong ability to resist crack corrosion The isocorrosion curve of SAF 2507 in sulfuric acid containing 2000ppm chloride ion is 0.1mm/year; Isocorrosion curve in hydrochloric acid 0.1 mm/year
