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Seamless 654SMO Super Stainless Steel Pipe

Seamless 654SMO Super Stainless Steel Pipe UNS S32654, W. Nr. 1.4652) is a high-performance super austenitic stainless steel alloy, often classified as a "super stainless steel" due to its exceptional corrosion resistance and mechanical strength. Developed for the most demanding environments, it features unusually high levels of chromium (24%), molybdenum (7-8%), nickel (23%), and nitrogen (0.45-0.55%), enabling pitting resistance equivalent number (PREN) values exceeding 50—comparable to top nickel-based alloys like Hastelloy. The seamless design ensures superior integrity for high-pressure, high-temperature, and corrosive applications, avoiding weld-related vulnerabilities. It is twice as strong as conventional austenitic grades like 304 or 316 while maintaining excellent ductility and toughness.
① STANDARD: ASTM A312/EN10216-5/GBT14976.

② OD RANGE : 6-706MM

③ THICKNESS RANGE: 1-48MM

654SMO/1.4652/UNSS32654 Chemical Composition

C

Si

Mn

Ni

P

S

Cr

Mo

N

Cu

≤0.02

≤0.50

2.00-4.00

21.00-23.00

≤0.03

≤0.005

23.00-25.00

7.00-8.00

0.45-0.55

0.30-0.16

654SMO/1.4652/UNSS32654 Mechanical Properties

Tensile strength (MPa)

0.2% proof strength (MPa)

Min. elongation at fracture (%)

Brinell hardness   (HB)

≥750

≥430

≥40

≤310

The ASTMA312 Size Tolerance


Standard

Outside Diameter

Thickness

Length

ASTM A312

O.D.

48.26mm

+0.40mm,

-0.80mm

Nominal Thickness ±12.5%

0mm to +6mm

48.26mm <

O.D.

114.3mm

±0.80mm,

114.3mm <

O.D.

219.08mm

+1.60mm,

-0.80mm

219.08mm <

O.D.

457.2mm

+2.40mm,

-0.80mm

457.2mm <

O.D.

660.4mm

+3.20mm,

-0.80mm

660.4mm <

O.D.

836.6mm

+4.00mm,

-0.80mm

863.6mm <

O.D.

+4.80mm,

-0.80mm


654SMO/1.4652/UNSS32654 Applications

  • 1) Refining, chemical equipment;
  • 2) Flue gas desulfurization device for thermal power generation, wastewater treatment;
  • 3) Atomic power generation, comprehensive utilization of coal, and ocean wave power generation;
  • 4) Marine structures in the sea environment, seawater desalination, marine aquaculture, seawater heat exchange;
  • 5) Salt production, soy sauce brewing food field;
  • 6) Paper industry, high concentration chloride ion environment of various bleaching devices;
  • 7) Oil and gas industry equipment;
  • 8) Offshore platforms, heat exchangers, underwater equipment, firefighting equipment;
  • 9) Chemical processing industry, utensils and pipeline industry;
  • 10) Desalted plants, high pressure RO plants and submarine pipelines;
  • 11) High-strength, corrosion-resistant mechanical equipment and components;
  • 12) Others.

One of our Services--Testing

  • EN 10204/3.1B, EN 10204 3.1 and EN 10204 3.2 Material Test Certificates (MTC)
  • Raw Materials Certificate
  • 100% Radiography Test Report
  • 100% PMI
  • Heat Treatment Charts
  • Third Party Inspection Report
  • Surface roughness and size measurement
  • Manufacturer Test Certificate( Impact Testing, Flatten, Spin,Curve, Hardness, Intergranular ,Point corrosions, Grain size, ET,UT, HT...)
  • Laboratory Test Certificate from Govt. Approved Lab
  • ......

654SMO/1.4652/UNSS32654 Material Summary


Seamless 654SMO Super Stainless Steel Pipe UNS S32654, W. Nr. 1.4652) is a high-performance super austenitic stainless steel alloy, often classified as a "super stainless steel" due to its exceptional corrosion resistance and mechanical strength. Developed for the most demanding environments, it features unusually high levels of chromium (24%), molybdenum (7-8%), nickel (23%), and nitrogen (0.45-0.55%), enabling pitting resistance equivalent number (PREN) values exceeding 50—comparable to top nickel-based alloys like Hastelloy. The seamless design ensures superior integrity for high-pressure, high-temperature, and corrosive applications, avoiding weld-related vulnerabilities. It is twice as strong as conventional austenitic grades like 304 or 316 while maintaining excellent ductility and toughness.

654SMo (S32654, 1.4652) super austenitic stainless steel features very good local corrosion resistance, good pitting resistance and good stress corrosion resistance under seawater, aeration, gap and low speed scouring conditions. It can be used as a good substitute to nickel-based alloys and titanium alloys. When it comes to high-temperature resistance or corrosion resistance, it is also superior to 904L and 254SMo.


Applications

  • Marine and Offshore: Seawater handling systems, desalination plants, submarine pipelines, heat exchangers.
  • Chemical Processing: Flue gas desulfurization, acid/chloride processing equipment, urea plants.
  • Energy and Power: Pressurized systems, flue gas cleaning, high-temperature seawater cooling.
Pulp/Paper and Pharma: Corrosive fluid piping, high-strength components.

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