Super Duplex UNS S32750 Pipe

Super Duplex stainless like S32750, is a mixed microstructure of austenite and ferrite (50/50) which has improved strength over ferritic and austenitic steel grades. The main difference is that Super Duplex has a higher molybdenum and chromium content which gives the material greater corrosion resistance than standard duplex grades.

Duplex 2507 is a super duplex stainless steel designed for applications which demand exceptional strength and corrosion resistance. Alloy 2507 has 25% chromium, 4% molybdenum, and 7% nickel. 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.

Chemical Composition (% by weight)

Element   Min       Max
C              -          0.03
Cr            24         26
Cu           0.5         1
Mn            -           2
Mo            3          5
N            0.24      0.35
Ni             6           8
P              -         0.35
S              -         0.015
Si             -           1

Mechanical Properties

          Temper                      Annealed

Tensile Rm                        115 ksi (min)
Tensile Rm                        800 MPa (min)
R.p. 0.2% Yield                 80 ksi (min)
R.p. 0.2% Yield                 550 MPa (min)
Elongation (2'' or 4D gl)       15 % (min)

Corrosion Resistance
2507 Duplex is highly resistant to uniform corrosion by organic acSuper Duplex 2507 Plateids 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.

The characteristics of Duplex 2507

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 degree
Low rate of thermal expansion
Combination of properties given by austenitic and ferritic structure
Good weldability and workability
 

Application:

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