Bar and Rod
Plate and Sheet
Strip
Pipe and Tube
Wire
Welding
Powder Material
Cast Products
Forged Products
Fittings
Fastening
Round Bar:
φ2–500 mm, 1–6 m length
Flat/Square Bar:
4–100 mm thickness/width
Hex Bar:
A/F 3–100 mm
Hollow Bar:
OD 20–300 mm
Sheet:
0.3–6 mm thickness
Medium Plate:
6–25 mm thickness
Heavy Plate:
25–100 mm thickness
Standard Strip:
0.05–3 mm thick,
10–600 mm wide
Precision strip:
0.01–0.5 mm thick,
tight tolerance ±0.005 mm
Foil:
0.005–0.1 mm thick
Seamless Tube:
OD 6–450 mm,
WT 1–50 mm,
1–12 m length
Welded Tube:
OD 10–600 mm,
WT 1–20 mm
Capillary Tube:
OD 1–10 mm,
WT 0.1–2 mm
Wire Form:
Cold Drawn Wire,
Bright Wire,
Spring Wire,
Fine Wire,
Ultra-fine Wire
General Diameter:
φ0.1–10 mm
Coil Weight:
50–500 kg,
customizable tolerance
Solid Wire:
φ0.8–4.0 mm
Flux-cored Wire:
φ1.2–4.0 mm
Welding Rod:
φ2.0–5.0 mm
Powder Form:
AM 3D Printing Powder,
Spherical Powder,
Gas-atomized Powder,
Water-atomized Powder
Particle Size:
10–150 μm
Sphericity:
≥90% for AM grade
Cast Ingot:
φ200–800 mm
Precision Casting:
min wall 0.5 mm
Cast Pipe:
OD 100–600 mm,
WT 10–50 mm
Forged Bar:
Φ35–500 mm
Forged Ring:
OD 200–2000 mm
Forging Weight:
1–5000 kg
Fittings Form:
Elbow, Tee, Reducer, Flange, Cap, Outlet, Lap Joint
Size range:
1/2''–24'' (DN15–DN600)
Wall thickness:
Sch10–Sch160, STD, XS, XXS
Pressure Class:
150–2500 LB
Fastening Form:
Bolt, Nut, Screw, Stud, Washer, Pin, Rivet
Metric: M3–M64
Imperial: #4–2.5''
Length: 6–500 mm
654SMO is a 7% molybdenum, high-nitrogen super-austenitic stainless steel — one of the most corrosion-resistant stainless steels produced. This datasheet presents the material within the American standard system.
With approximately 24% chromium, 22% nickel, 7.3% molybdenum and 0.5% nitrogen, 654SMO has a pitting-resistance equivalent number (PREN) above 56, placing its localized-corrosion resistance close to that of nickel-base alloys and titanium. Its nitrogen content is roughly twice that of the 6Mo grade 254SMO, giving it higher mechanical strength while retaining good ductility, toughness and weldability. The alloy resists pitting, crevice corrosion and chloride stress-corrosion cracking in aggressive chloride and seawater environments.
Typical applications include chlorinated seawater systems, flue-gas desulphurization plant, seawater heat exchangers, desalination equipment, bleach plants and other high-halide process equipment where 6Mo grades are insufficient.
Values for the solution-annealed condition.
| Property | Value | Unit |
|---|---|---|
| Density | 8.0 | g/cm³ |
| Melting range | 1410–1450 | °C |
| Young's modulus (20 °C) | 210 | GPa |
| Thermal conductivity (20 °C) | 11 | W/m·K |
| Coefficient of thermal expansion (20–100 °C) | 15 | µm/m·°C |
| Specific heat (20 °C) | 460 | J/kg·K |
| Electrical resistivity (20 °C) | ~0.78 | µΩ·m |
| Magnetic response | Non-magnetic (austenitic) | — |
Composition per ASTM A240.
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | Balance | — | Base element |
| Chromium | Cr | 24.0 | 25.0 | Passivity; pitting resistance |
| Nickel | Ni | 21.0 | 23.0 | Austenite stability; SCC resistance |
| Molybdenum | Mo | 7.0 | 8.0 | Pitting + crevice resistance |
| Manganese | Mn | 2.0 | 4.0 | Austenite stability; raises N solubility |
| Nitrogen | N | 0.45 | 0.55 | High strength; pitting resistance |
| Copper | Cu | 0.30 | 0.60 | Reducing-acid resistance |
| Silicon | Si | — | 0.50 | Deoxidiser |
| Carbon | C | — | 0.020 | Very low (intergranular resistance) |
| Phosphorus | P | — | 0.030 | Residual impurity |
| Sulphur | S | — | 0.005 | Residual impurity |
Nominal: 24Cr-22Ni-7.3Mo-0.5N. PREN = %Cr + 3.3×%Mo + 16×%N ≈ 56–57.
Solution-annealed condition, per ASTM A240 for UNS S32654.
| Property | Value | Unit |
|---|---|---|
| Tensile strength | ≥750 | MPa |
| 0.2% yield strength | ≥430 | MPa |
| Elongation at break | ≥40 | % |
| Brinell hardness | ≤250 | HB |
Typical solution-annealed values are higher (UTS ~850 MPa, yield ~490 MPa); confirm against the mill test report.
| Environment | Performance | Notes |
|---|---|---|
| Chloride pitting | Outstanding | PREN > 56; CPT often > 90 °C |
| Crevice corrosion | Outstanding | Among the best of stainless steels |
| Chloride SCC | Excellent | High Ni + N |
| Seawater (chlorinated) | Excellent | Resists warm chlorinated seawater |
| Reducing acids | Good | Mo + Cu assist |
| Oxidizing acids | Excellent | High Cr |
The alloy approaches nickel-base alloys and titanium in seawater and high-halide service.
A solid-solution alloy; it is not hardenable by heat treatment.
Solution Anneal approximately 1150–1200 °C, followed by rapid quenching (water) to retain nitrogen in solution and dissolve secondary phases. Because of its high alloy content, sufficiently rapid cooling is essential to avoid intermetallic precipitation.
Weldable by GTAW, GMAW and SMAW. Owing to its high alloy content, an over-alloyed nickel-base filler is normally used to match corrosion resistance in the weld.
| Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Excellent | Over-alloyed Ni-base (e.g. ERNiCrMo-type) |
| GMAW / MIG | Good | Over-alloyed Ni-base |
| SMAW / stick | Good | Matching Ni-base electrode |
No preheat; keep interpass temperature low and heat input controlled to avoid intermetallic precipitation.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Difficult; high strength + work-hardening; rigid setup, sharp tooling, slow speeds, positive feeds |
| Work hardening | High rate; avoid dwelling |
| Coolant | Ample flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Work-hardens rapidly; higher forces than standard austenitics |
| Hot forming | ~1150–1200 °C; solution anneal + quench afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Marine / seawater | Chlorinated seawater piping, pumps, valves | Pitting + crevice resistance |
| Pulp & paper | Bleach-plant equipment | Halide + acid resistance |
| Flue-gas desulphurization | Scrubbers, ducting | Chloride + acid resistance |
| Desalination | Heat exchangers, evaporators | Hot chloride resistance |
| Chemical processing | Process equipment in high-halide media | General + localized resistance |
| Product Form | Standard | Notes |
|---|---|---|
| Plate, sheet and strip | ASTM A240 / ASME SA-240 · UNS S32654 | — |
| Bar and shapes | ASTM A479 / ASME SA-479 · UNS S32654 | — |
| Seamless / welded pipe | ASTM A312 · UNS S32654 | — |
| Seamless / welded tube | ASTM A269 / A249 · UNS S32654 | — |
| Forgings / fittings | ASTM A182 · UNS S32654 | — |
| Sour service | NACE MR0175 / ISO 15156 | Acid-gas applications |
7Mo super-austenitic stainless steel. UNS S32654.
| UNS | Cr % | Mo % | N % | PREN | Best Used For |
|---|---|---|---|---|---|
| S32654 | 24–25 | 7.0–8.0 | 0.45–0.55 | ~56 | Most severe seawater / halide service |
| S31254 (254SMO) | 19.5–20.5 | 6.0–6.5 | 0.18–0.22 | ~43 | 6Mo seawater service |
| N08367 (AL-6XN) | 20–22 | 6.0–7.0 | 0.18–0.25 | ~45 | 6Mo seawater service |
| N08926 (926) | 19–21 | 6.0–7.0 | 0.15–0.25 | ~43 | 6Mo seawater service |
| N08904 (904L) | 19–23 | 4.0–5.0 | — | ~35 | Sulphuric-acid service |
021-33556635
13371897780
651280525@qq.com
No. 600, Si Chuang Road, Songjiang District, Shanghai
