UNS 32750 Super Duplex Seamless Stainless Steel Tubes

UNS 32750 Super Duplex Stainless Steel Pipes and Tubes

Super Duplex Stainless Steel is a highly alloyed, good performance Duplex steel with a pitting resistance. Super Duplex offers good resistance to pitting and crevice corrosion. Super Duplex is suited for use in aggressive environments. Super Duplex Stainless has good resistance to stress corrosion cracking in chloride and sour environments. Super Duplex has good resistance to erosion corrosion and corrosion fatigue.
Super Duplex stainless like Duplex, 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.
Stainless Steel Super Duplex 2507 is designed for applications which demand exceptional strength and corrosion resistance. The high molybdenum, chromium and nitrogen content in Super Duplex 2507 results in excellent resistance to chloride pitting and crevice corrosion attack and the duplex structure provides Super Duplex 2507 with exceptional resistance to chloride stress corrosion cracking. Usage of Super Duplex Steel 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.
Super Duplex has the same benefits as its counterpart - it has lower production costs when compared with similar ferritic and austenitic grades and due to the materials increased tensile and yield strength, in many cases this gives the purchaser the welcomed option of purchasing smaller thicknesses without the need to compromise on quality and performance.
Benefits of UNS32750 Super Duplex Stainless Steel
Improved corrosion resistance in comparison to Duplex
Greater tensile and yield strength
Good ductility and toughness
Good stress corrosion cracking resistance (SSC)
Opportunity for purchases to reduce their material costs without compromising on quality
Corrosion Resistance
General Corrosion
The high chromium and molybdenum content of 2507 makes it extremely resistant to uniform corrosion by organic acids like formic and acetic acid. 2507 also provides excellent resistance to inorganic acids, especially those containing chlorides.
In dilute sulfuric acid contaminated with chloride ions, 2507 has better corrosion resistance than 904L, which is a highly alloyed austenitic steel grade specially designed to resist pure sulfuric acid.
Stainless steel of type 316L (2.5%Mo) cannot be used in hydrochloric acid due to the risk of localized and uniform corrosion. However, 2507 can be used in dilute hydrochloric acid. Pitting need not be a risk in the zone below the borderline in this figure, but crevices must be avoided.
Isocorrosion curves, 0.1 mm/year, in sulfuric acid
With an addition of 2000 ppm chloride ions
Isocorrosion curves, 0.1 mm/year, in hydrochloric acid.
Broken line curve represents the boiling point
Critical Pitting Temperature (CPT) range for
Various alloys in 1M NACl
Critical Crevice Corrosion Temperature (CCT)
For various alloys in 10% FeCl3
Intergranural Corrosion
2507's low carbon content greatly lowers the risk of carbide precipitation at the grain boundaries during heat treatment; Therefore, the alloy is highly resistant to carbide-related intergranular corrosion.
Stress Corrosion Cracking
The duplex structure of 2507 provides excellent resistance to chloride stress corrosion cracking (SCC). Because of its higher alloy content, 2507 is superior to 2205 in corrosion resistance and strength. 2507 is especially useful in offshore oil and gas applications and in wells with either naturally high brine levels or where brine has been injected to enhance recovery.

Chemical Analysis
Typical values (Weight %)

Mechanical Properties
Mechanical and Physical Properties
2507 combines high tensile and impact strength with a low coefficient of thermal expansion and high thermal conductivity. These properties are suitable for many structural and mechanical components. The low, ambient, and elevated temperature mechanical properties of 2507 sheet and plate are shown below. All of the test data shown are for samples in the annealed and quenched condition.
2507 is not recommended for applications which require long exposures to temperatures in excess of 570 0 F because of the increased risk of a reduction in toughness. The data listed here are typical for wrought products and should not be regarded as a maximum or minimum value unless specifically stated.

Mechanical Properties

Low Temperature Impact Properties