ASME SA789 / ASTM A789 S32750 Duplex Stainless Steel Seamless Tube for Heat Exchanger, Chemical Application

ASME SA798 / ASTM A789 specifies the dimensional tolerances, process requirements, and testing methods for seamless and welded duplex stainless steel pipes. The common specifications under this standard are an outer diameter range of 6-1200 mm and a wall thickness of 0.5-50 mm. Large caliber or thick walled pipes can be customized. Its testing requirements include hydrostatic testing, non-destructive testing (UT/RT), intergranular corrosion testing (according to standard ASTM A262), etc.

ASTM A789 S32750 (UNS S32750 2507 duplex stainless steel) is a high-performance super duplex stainless steel tube that combines the advantages of austenite and ferrite duplex structures, with excellent corrosion resistance, high strength, and good processability. The chemical composition of S32750 is mainly chromium (Cr): 24-26%, nickel (Ni): 6-8%, molybdenum (Mo): 3-4%, nitrogen (N): 0.24-0.32%, manganese (Mn): ≤ 1.2%, carbon (C): ≤ 0.03%.

ASTM A789 S32750 Duplex Stainless Steel Heat Exchanger Tube Chemical Composition

ASTM A789 S32750 Duplex Stainless Steel Seamless Heat Exchanger Tube Mechanical Properties

ASTM A789 S32750 Duplex Stainless Steel Advantage comparison:

• Corrosion resistance: S32750 duplex steel heat exchanger tube has better corrosion resistance than conventional duplex steel (such as 2205) and austenitic stainless steel (316L), especially in chloride ion and acidic media.
• Economy: The cost of S32750 duplex steel is 30-50% lower than that of nickel based alloys (such as Hastelloy C276), and the cost-effectiveness is significant.
• Lightweight: The high-strength characteristics of S32750 duplex steel can reduce the wall thickness of pipes and lower installation and maintenance costs.

ASTM A789 S32750 Duplex Stainless Steel Seamless Tube Core application areas:

(1) Severe corrosive environment

Marine engineering: high-pressure pipelines for seawater desalination, subsea oil pipelines, and ship cooling systems.

Oil and gas industry: oil and gas well pipelines with high H ₂ S/CO ₂ content, and gathering and transportation pipelines in acidic environments.

Chemical equipment: reactors, heat exchangers, and valves for concentrated hydrochloric acid and chloride containing ion media.

(2) High stress scenario

High pressure heat exchange tube: resistant to corrosion and deformation under high temperature (≤ 300 ℃) and high pressure.

Structural support components: offshore platform supports, load-bearing parts of chemical equipment, utilizing high yield strength to reduce material usage.

(3) Special industrial needs

Pulp and paper: High temperature chlorate medium pipeline in bleaching section.

Flue gas desulfurization (FGD): Spray pipes and flues for wet flue gas desulfurization systems in coal-fired power plants.

Nuclear power plant: corrosion-resistant pipelines for seawater circulation cooling system.