ASME SA789 UNS S32750 Super Duplex Stainless Steel Seamless Tube For Condenser

ASME SA789 UNS S32750 Super Duplex Stainless Steel Seamless Tube For Condenser

What is ASME SA789 UNS S32750 Super Duplex Stainless Steel Seamless Tube?

ASME SA789 UNS S32750 Super Duplex Stainless Steel Seamless Tube is a specification for seamless tubes made from UNS S32750, a super duplex stainless steel. This material is known for its exceptional combination of high strength, excellent corrosion resistance, and good toughness, making it suitable for demanding applications in harsh environments. The ASME SA789 standard specifies the requirements for seamless and welded stainless steel tubes used in general service and corrosive environments.

Key Features of UNS S32750 Super Duplex Stainless Steel

• High Strength: UNS S32750 has a higher yield strength compared to standard duplex and austenitic stainless steels, making it suitable for high-pressure applications.
• Excellent Corrosion Resistance:It offers superior resistance to pitting, crevice corrosion, and stress corrosion cracking (SCC), especially in chloride-rich environments like seawater.
• Balanced Microstructure: The material has a dual-phase microstructure (approximately 50% austenite and 50% ferrite), which contributes to its strength and corrosion resistance.
• Good Weldability and Fabricability:UNS S32750 can be welded and fabricated using standard techniques, though proper procedures must be followed to maintain its properties.
• Resistance to Acids and Chemicals: It performs well in environments with acids, alkalis, and other corrosive chemicals.

ASME SA789 Specification:

The ASME SA789 standard covers the requirements for seamless and welded stainless steel tubes used in general service and corrosive environments. Key aspects of the specification include:

- Material Composition:

UNS S32750 has a specific chemical composition, including high levels of chromium (Cr), molybdenum (Mo), and nitrogen (N):

Chromium (Cr): 24–26%

Molybdenum (Mo): 3–4%

Nickel (Ni): 6–8%

Nitrogen (N): 0.24–0.32%

-Mechanical Properties:

Tensile Strength: ≥ 800 MPa (116 ksi)

Yield Strength: ≥ 550 MPa (80 ksi)

Elongation: ≥ 15%

- Dimensional Tolerances:

The standard specifies tolerances for outer diameter, wall thickness, and length of the tubes.

-Testing Requirements:

Tubes must undergo hydrostatic testing or non-destructive testing (NDT) to ensure integrity.

Additional tests, such as pitting resistance testing (ASTM G48), may be required to verify corrosion resistance.

-Heat Treatment:

Tubes are typically supplied in the solution-annealed condition to optimize corrosion resistance and mechanical properties.

What's the application of A789 UNS S32750 seamless tubes?

A789 UNS S32750 seamless tubes are made from a super duplex stainless steel known for its high strength and excellent corrosion resistance. These properties make them suitable for a variety of demanding applications, particularly in industries where materials are exposed to harsh environments. Here are some common applications:

1. Oil and Gas Industry

Offshore and Onshore Pipelines: UNS S32750 tubes are used in the transportation of oil and gas, especially in environments with high chloride content, such as seawater.

Downhole and Subsea Equipment: These tubes are used in components like umbilicals, risers, and flowlines due to their resistance to pitting, crevice corrosion, and stress corrosion cracking.

2. Chemical and Petrochemical Industry

Heat Exchangers and Condensers: The high corrosion resistance of UNS S32750 makes it ideal for heat exchangers and condensers that handle aggressive chemicals.

Process Piping: These tubes are used in piping systems that transport corrosive chemicals, acids, and solvents.

3. Desalination Plants

Seawater Desalination: UNS S32750 tubes are used in desalination plants for components like heat exchangers and piping systems due to their resistance to chloride-induced corrosion.

4. Power Generation

Nuclear and Fossil Fuel Power Plants: These tubes are used in heat exchangers, condensers, and feedwater systems where high strength and corrosion resistance are required.

Flue Gas Desulfurization (FGD) Systems: UNS S32750 tubes are used in FGD systems to handle corrosive gases and liquids.

5. Marine and Shipbuilding

Seawater Cooling Systems: The tubes are used in seawater cooling systems and other marine applications due to their excellent resistance to seawater corrosion.

Propulsion Systems: UNS S32750 is used in components like shafts, propellers, and pumps in marine environments.

6. Pulp and Paper Industry

Bleaching Equipment: The tubes are used in bleaching equipment and other areas where exposure to corrosive chemicals is common.

7. Pharmaceutical Industry

High-Purity Systems: UNS S32750 tubes are used in high-purity systems where corrosion resistance and cleanliness are critical.

8. Food and Beverage Industry

Sanitary Processing Equipment: The tubes are used in sanitary processing equipment where resistance to corrosion and ease of cleaning are important.

9. Water Treatment

Wastewater Treatment Plants: UNS S32750 tubes are used in wastewater treatment plants for components like pumps, valves, and piping systems.

10. Aerospace and Defense

High-Strength Components: The high strength and corrosion resistance of UNS S32750 make it suitable for certain aerospace and defense applications where these properties are required.