654SMO Super Austenitic Stainless Steel (UNS S32654)
654SMO is a super austenitic stainless steel with 25% chromium, 23% nickel, and 7% molybdenum that has corrosion resistance comparable to the best nickel-based alloys and can replace iron-nickel-based or even nickel-based corrosion-resistant alloys in many media, thus filling the gap between stainless steel and high-nickel corrosion-resistant alloys without high resistance to pitting and crevice corrosion. The nitrogen content of 654SMO super austenitic stainless steel is twice that of 254SMO alloy, which has a better tensile strength than 904L and 254SMO.
In solid solution, 654SMO alloy possesses superior plasticity, toughness, and strength qualities to conventional austenitic and 6% Mo austenitic stainless steel; its mechanical properties are even equivalent to some nickel-based corrosion-resistant alloys. In seawater, and inflatables, with the presence of gaps, low-speed scouring conditions, strong resistance to pitting corrosion, and good stress corrosion resistance, 654SMO super austenitic stainless steel has extremely good local corrosion resistance. Stress corrosion resistance is a material replacement for nickel-based alloys and titanium alloys. Second, it is more resistant to high temperatures and corrosion than 904L and 254SMO.
654 SMO has superior corrosion resistance in waste incineration plant gas cooling media not only to super austenitic stainless steel 254 SMO and super duplex stainless steel containing 6% Mo but also to the high chromium and molybdenum nickel-based corrosion resistant alloys Inconel 625, Hastelloy C276, Hastelloy C22, and titanium Gr2.
Chemical Composition (%) of 654SMO Super Austenitic Stainless Steel (UNS S32654)
| CHEMICAL COMPOSITION (%) | ||||||||||
| C, max | Mn | P, max | S, max | Si, max | Cr | Ni | Mo | Cu | Fe | N |
| 0.02 | 2.00-4.00 | 0.030 | 0.005 | 0.05 | 23.00-25.00 | 21.00-23.00 | 7.00-8.00 | 0.30-0.60 | Rest | 0.45-0.55 |
Mechanical Properties of 654SMO Super Austenitic Stainless Steel (UNS S32654)
| MECHANICAL PROPERTIES | |||
| Tensile Strength, MPa, min | Yield Strength, MPa, min | Elongation (%), min | Hardness, max |
| 750 | 430 | 40 | 250 HB |
Physical Properties of 654SMO Super Austenitic Stainless Steel (UNS S32654)
| PHYSICAL PROPERTIES | ||||||
| Density | Melting Point | Modulus of Elasticity | Poisson's Ratio | Coefficient of Thermal Expansion | Thermal Conductivity | Electrical Conductivity |
| 8.24 g/cm³ | 1320-1390℃ | 210 GPa | 0.28 | 15 µm/m·K | 9.8 W/m·K | 2.2% IACS |
Heat Treatment Temperature: 1100-1150 °C
Features of 654SMO Super Austenitic Stainless Steel (UNS S32654)
- Non-magnetic
- Excellent resistance to localized corrosion
- Excellent resistance to pitting
- Excellent resistance to stress corrosion
- Good heat resistance
- Good tensile strength
- Good plasticity
- Good toughness
Applications of 654SMO Super Austenitic Stainless Steel (UNS S32654)
654SMO super austenitic stainless steel is mainly used in the chemical industry, marine, paper, and other industries.
- Seawater desalination equipment
- Petrochemical machinery and equipment
- Flue gas desulfurization equipment
- Heat exchangers
- Wastewater treatment system
- Corrosion-resistant industrial equipment
Equivalent Grades of 654SMO Super Austenitic Stainless Steel (UNS S32654)
| ASTM | UNS | WERKSTOFF NR. | GB | EN |
| 654SMO | S32654 | 1.4652 | 00Cr24Ni22Mo7Mn3CuN | X1CrNiMoCuN24-22-8 |
