ASTM A790 UNS S32750(Duplex 2507) is a super duplex stainless steel with 25% chromium, 4% molybdenum, and 7% nickel, it can be the Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe. This high molybdenum, chromium and nitrogen content results in excellent resistance to chloride pitting and crevice corrosion attack and the duplex structure provides 2507 with exceptional resistance to chloride stress corrosion cracking.
Usage of Duplex 2507 should be limited to applications below 600° F (316° C). Extended elevated temperature exposure can reduce both the toughness and corrosion resistance of alloy 2507.
Duplex 2507 possesses excellent mechanical properties. Often a light gauge of 2507 material can be used to achieve the same design strength of a thicker nickel alloy. The resulting savings in weight can dramatically reduce the overall cost of fabrication.
Corrosion Resistance:
2507 Duplex is highly resistant to uniform corrosion by organic acids such as formic and acetic acid. It is alsohighly resistant to inorganic acids, especially if they contain chlorides. Alloy 2507 is highly resistant to carbide-related intergranular corrosion. Due to the ferritic portion of the duplex structure of the alloy it is very resistant to stress corrosion cracking in warm chloride containing environments. Through additions of chromium, molybdenum and nitrogen localized corrosion such as pitting and crevice attack are improved. Alloy 2507 has excellent localized pitting resistance.
What are the characteristics of Duplex 2507 or S32750?
High resistance to chloride stress corrosion cracking
High Strength
Superior resistance to chloride pitting and crevice corrosion
Good general corrosion resistance
Suggested for applications up to 600° F
Low rate of thermal expansion
Combination of properties given by austenitic and ferritic structure
Good weldability and workability
Super Duplex 2507 Pipes Chemical Composition:
| Grade |
C≤ |
Mn≤ |
P≤ |
S≤ |
Si≤ |
Ni |
Cr |
Mo |
N |
Cu |
| S32750 |
0.03 |
1.20 |
0.035 |
0.02 |
0.80 |
6.0-8.0 |
24.0-26.0 |
3.0-5.0 |
0.24-0.32 |
0.5 |
| S32760 |
0.05 |
1.00 |
0.03 |
0.01 |
1.00 |
6.0-8.0 |
24.0-26.0 |
3.0-4.0 |
0.20-0.30 |
0.50–1.00 |
Mechanical Properties of Super Duplex S32750 Pipes and Tubes:
| Mechanical properties |
Tensile, min, ksi[MPa] |
Yield, min, ksi[MPa] |
Elongation, %(min) |
Hardness, HB（max） |
| S32750 |
116 [800] |
80 [550] |
15 |
300 |
| S32760 |
109 [750] |
80 [550] |
25 |
300 |
The applications of super duplex stainless steel S32750 are:
Desalination Equipment.
Chemical process pressure vessels, piping and heat exchangers.
Marine Applications.
Flue Gas Scrubbing Equipment.
Pulp & Paper Mill Equipment.
Offshore Oil production/technology.Oil and gas industry equipment.
