The duplex 2205 and super duplex 2507 stainless steel seamless pipes are the best grades of stainless steel seamless pipes due to their excellent corrosion resistance, toughness and high strength.
Both alloys used chromium, nickel, and molybdenum as basic elements in their composition.
The super duplex 2507 stainless steel seamless pipes have more chromium, nickel, and molybdenum contents than the duplex 2205 stainless steel seamless pipes.
Duplex 2507 stainless steel pipes have outstanding corrosion resistance properties. Due to the high contents of chromium and nickel in its composition, duplex 2507 stainless steel alloys are mostly used in harsh corrosive environments.
Duplex 2205 and duplex 2507 stainless steel seamless pipes play a vital role in the petrochemical and chemical processing industries.
In this article, you can learn more about difference between them, and choose the best grade of duplex stainless steel for your project.
What is Duplex 2205 Stainless Steel Seamless Pipe?
Due to its dual ferritic and austenitic characteristics, duplex 2205 stainless steel pipe is widely utilized in applications that demand both high strength and corrosion resistance.
2205 stainless steel seamless pipe is a duplex stainless steel material composed of 22% chromium, 2.5% molybdenum and 4.5% nickel-nitrogen alloy. It is also called UNS S31803 tube.
The stainless steel grade UNS S31803 has undergone several revisions to become UNS S32205, which was approved in 1996. This grade provides greater corrosion resistance.
Due to its excellent corrosion properties, duplex 2205 pipe is a highly suitable material for service in environments containing chlorides and hydrogen sulphide.
To overcome frequent corrosion issues with the 300 series stainless steels, duplex 2205 stainless steel, nitrogen-enhanced duplex stainless steel, was created. The austenite pools and continuous ferrite phase make up the structure of 2205 duplex stainless steel. Duplex 2205 stainless steel alloy has between 40 and 50 percent ferrite when it is annealed.
The most popular grade in the duplex family of stainless steel, duplex 2205, is one of the industry’s most commonly used grades. A duplex construction combines the benefits of an austenitic alloy’s ease of manufacturing and corrosion resistance with the stress corrosion cracking resistance and high strength of a ferritic alloy.
What is Super Duplex 2507 Stainless Steel Seamless Pipe?
Super duplex 2507 stainless steel seamless pipe is made to handle very corrosive environments and circumstances where great strength is required.
Super duplex 2507 stainless steel alloy has high molybdenum, chromium, and nitrogen composition to help the material’s resistance against pitting and crevice corrosion.
The material is also resistant to general corrosion in acids, corrosion fatigue, and cracking caused by chloride stress corrosion. This alloy is very strong mechanically and has good weldability.
The stainless steel grade duplex 2507 is also known as (UNS S32750). Duplex 2507 stainless steel seamless pipes should only be used for temperatures below 600° F (316° C).
2507 stainless steel seamless pipe is also called EN 1.4410 tube, which combines the most beneficial properties of many ferritic stainless steel seamless pipe (430 stainless steel seamless pipe) and austenitic stainless steel seamless pipe (such as 310S stainless steel seamless pipe).
Alloy 2507’s hardness and corrosion resistance may be reduced by continuous exposure to high temperatures.
Duplex 2507 stainless steel has superior mechanical qualities. It is frequently possible to utilize a thin gauge of 2507 material to attain the same design strength as a thicker nickel alloy. The weight savings that occur can significantly lower the fabrication cost. The organic acids formic and acetic acid do not easily corrode duplex 2507 stainless steel seamless pipe.
Grade Duplex 2205 Stainless Steel Seamless Pipe Vs. Grade Super Duplex 2507 Stainless Steel Seamless Pipe Comparison
Let’s see the comparison of duplex 2205 stainless steel pipe and super duplex 2507 stainless steel pipe with their composition and properties.
Chemical Composition Comparison
| Alloy Grade | C | Si | Mn | Cr | Ni | S | P | Mo | N |
| 2205 (UNS S32205) | < 0.03 | 1 max | < 2.0 | 22.0-23.0 | 4.5-6.5 | 0.02 max | 0.030 max | 3.0-3.5 | 014-0.20 |
| 2507 (UNS S32750) | < 0.03 | 0.80 max | < 1.20 | 24.0-26.0 | 6.0-8.0 | 0.02 max | 0.035 max | 3.0-5.0 | 0.24-0.32 |
Mechanical Properties Comparison
| Alloy Grade | Tensile Strength Rm(MPa) | Yield Strength (0.2%Offset) (MPa) | Elongation (%) |
| 2205 (UNS S32205) | ≥620 | ≥450 | ≥25 |
| 2507 (UNS S32750) | ≥800 | ≥550 | ≥25 |
Equivalent Grades Comparison
| STANDARD | Duplex 2205 |
| WERKSTOFF NR. | 1.4462 |
| UNS | S31803, S32205 |
| STANDARD | Super Duplex 2507 |
| WERKSTOFF NR. | 1.4410 |
| UNS | S32750 |
Corrosion Resistance Comparison
Due to the difference in chemical composition, super duplex 2507 stainless steel seamless pipe is more resistant to corrosion than 2205 stainless steel seamless pipe, especially in environments containing chloride ions and acidic environments.
Under the same conditions, 2507 is more resistant to corrosion, wear, pitting, and intergranular corrosion than 2205 grade alloy.
What are the Grade Duplex 2205 Stainless Steel Seamless Pipe and Grade Super Duplex 2507 Stainless Steel Seamless Pipe Applications?
Applications of duplex 2205 stainless steel pipes:
Chromium, molybdenum, and nitrogen work together to give duplex 2205 stainless steel pipes good resistance to crevice corrosion and chloride pitting. This resistance is essential for services like marine environments, bleaching processes, closed-loop water systems, and some food processing applications.
Duplex 2205 stainless steel alloy is also used in heat exchangers and oil field piping. In most settings, duplex 2205’s high chromium, molybdenum, and nitrogen concentrations offer corrosion resistance that is superior to that of typical stainless steel pipes like 316L and 317L.
Applications of duplex 2507 stainless steel seamless pipes:
Duplex 2507 stainless steel pipes are widely used in the following applications.
- Tools for the oil and gas industry
- Heat exchangers, injection and ballast water systems, water process and service systems, firefighting equipment
- Industries including chemical processes, heat exchangers, vessels and pipes
- Seawater pipes, high-pressure RO systems
- Structural and mechanical elements, as well as solid and corrosion-resistant parts
- Utility and industrial scrubber systems, absorption towers, ducting, and piping and for the power industry
Which one between Grade Duplex 2205 Stainless Steel Seamless Pipe and Grade Duplex 2507 Stainless Steel Seamless Pipe is better?
Duplex 2507 stainless steel seamless pipe is better than super duplex 2205 stainless steel pipe due to some extra contents of chromium-nickel and molybdenum in its composition.
The super duplex 2507 stainless steel pipe has excellent corrosion resistance against organic acids like acetic and formic acid. It is also quite resistant to inorganic acids, particularly if they contain chlorides.
Conclusion
Duplex 2205 and duplex 2507 stainless steel seamless pipes have some similarities and differences in their compositions.
Both of these stainless steel alloys pipes are most commonly used in industries.
Most people demand these alloys due to their outstanding properties like corrosion resistance, high strength, and toughness.
We specialize in the production of premium-grade duplex stainless steel pipes products. If you have new project today, please do not hesitate to contact our expert team.
