Super Austenitic
Stainless Steel
Mill-Certified, Ship in 30 Days
Precision-cut super austenitic stainless steel in grades 254SMO, 654 SMO, 904L, AL-6XN, and 20Mo-6 — supplied with full EN 10204 3.1 MTC, ASTM / EN / JIS compliance, and third-party inspection from Hunan Fushun Metal Co., Ltd.
Five Core Grades
Super Austenitic Stainless Steel Grades
All five super austenitic stainless steel grades are produced to ASTM, EN, DIN, JIS, and BS standards with full material traceability from melt to delivery. Select a grade to match your corrosion resistance and mechanical requirements.
ASTM A276 / A240 / A276M
Seawater piping, heat exchangers, desalination, offshore platform tubing, flue gas scrubbers.
ASTM A276 / A240
Bleaching circuits, FGD scrubbers, concentrated brine, aggressive acid-chloride services.
ASTM B625 / B649 / B672
Sulfuric & phosphoric acid systems, petrochemical heat exchangers, pulp digesters, food processing.
ASTM B625 / B649 / B673
Seawater desalination, marine heat exchangers, offshore risers, chemical plant piping.
ASTM B463 / B464 / B474
Phosphoric acid production, sulfuric acid coolers, fertiliser plant equipment, reducing acid services.
Response within 24 business hours · No minimum for stock enquiries
Technical Specifications
Super Austenitic Stainless Steel — Chemical & Mechanical Properties
All compositions meet ASTM/EN/JIS requirements. Values below are nominal ranges; certified actual chemistry and mechanical data are supplied on the EN 10204 3.1 MTC for every heat.
| Grade (UNS) | C max | Cr | Ni | Mo | Cu | N | Mn max | Si max | S max | P max |
|---|---|---|---|---|---|---|---|---|---|---|
| 254SMO (S31254) | 0.020 | 19.5 – 20.5 | 17.5 – 18.5 | 6.0 – 6.5 | 0.50 – 1.00 | 0.18 – 0.22 | 1.00 | 0.80 | 0.010 | 0.030 |
| 654 SMO (S32654) | 0.020 | 24.0 – 25.0 | 21.0 – 23.0 | 7.0 – 8.0 | 0.30 – 0.60 | 0.45 – 0.55 | 2.00 – 4.00 | 0.50 | 0.005 | 0.030 |
| 904L (N08904) | 0.020 | 19.0 – 23.0 | 23.0 – 28.0 | 4.0 – 5.0 | 1.00 – 2.00 | 0.10 max | 2.00 | 1.00 | 0.035 | 0.045 |
| AL-6XN (N08367) | 0.030 | 20.0 – 22.0 | 23.5 – 25.5 | 6.0 – 7.0 | 0.75 max | 0.18 – 0.25 | 2.00 | 1.00 | 0.030 | 0.040 |
| 20Mo-6 (N08026) | 0.030 | 22.0 – 26.0 | 33.0 – 37.2 | 5.0 – 6.5 | 2.00 – 4.00 | 0.10 max | 1.00 | 0.50 | 0.030 | 0.030 |
Source: ASTM / EN standards & certified MTC data. Orange cells = key differentiating elements.
| Grade (UNS) | 0.2% Yield (MPa) | Tensile (MPa) | Elongation (%) | Hardness (HB max) | PREN (nominal) |
|---|---|---|---|---|---|
| 254SMO (S31254) | ≥ 300 | ≥ 650 | ≥ 40 | 223 | 43 |
| 654 SMO (S32654) | ≥ 430 | ≥ 750 | ≥ 40 | 250 | 54 |
| 904L (N08904) | ≥ 220 | ≥ 520 | ≥ 35 | 200 | 36 |
| AL-6XN (N08367) | ≥ 310 | ≥ 690 | ≥ 30 | 241 | 46 |
| 20Mo-6 (N08026) | ≥ 220 | ≥ 600 | ≥ 30 | 217 | 40 |
PREN = %Cr + 3.3 × %Mo + 16 × %N. Values are calculated from nominal composition midpoints. Actual certified values on MTC may differ. Values shown meet ASTM and EN minimums.
Available Forms & Sizes
Super Austenitic Stainless Steel — Dimensions & Product Forms
Standard and custom dimensions available across all five super austenitic grades. Contact our team with drawings or specifications for a feasibility check within 24 business hours.
Round Bar
- Diameter
- 3 – 500 mm
- Length
- 1,000 – 6,000 mm / cut-to-length
- Tolerance
- h9 / h11 / custom
Flat Bar
- Thickness × Width
- 3–100 mm × 10–600 mm
- Length
- 1,000 – 6,000 mm / custom
- Tolerance
- EN 10278 / custom
Plate
- Thickness
- 3 – 120 mm
- Width × Length
- Up to 3,000 × 12,000 mm
- Tolerance
- EN 10029 Class A/B
Sheet & Strip
- Thickness
- 0.3 – 3.0 mm (strip) / 3 – 10 mm (sheet)
- Width
- Up to 1,500 mm
- Finish
- 2B / BA / No.1 / No.4
Coil
- Thickness
- 0.3 – 3.0 mm
- Width
- 100 – 1,500 mm
- Weight / coil
- Up to 2,000 kg
Wire
- Diameter
- 0.1 – 10 mm
- Condition
- Annealed / hard / coated
- Spool weight
- As required
Logistics & Packaging
Fast, Traceable Delivery Worldwide
From order confirmation to freight handover, our logistics team coordinates documentation, packing inspection, and customs clearance to minimise downtime for your project.
Stock standard sizes — ready inventory, immediate MTC issue, rapid dispatch from Changsha warehouse.
Custom dimensions or large-volume orders — dedicated production scheduling from confirmed PO.
No minimum quantity restriction on stock cuts. Custom production MOQ is 3 metric tons per grade.
Packaging Options
Packaging is selected to suit transit mode, climate, and destination port requirements.
Standard Bundle
Steel-strapped bare bundles with identification tags. Suitable for short-haul land freight with covered transport.
Anti-Rust Protected
Anti-rust oil coating + LDPE film wrap + steel strapping. For sea or air freight to humid climates.
Export Wooden Crate
ISPM-15 fumigated crate with desiccant packs, foam padding, and vacuum sealing for FCL / LCL sea freight.
Manufacturing
Vertically Integrated Production of Super Austenitic Stainless Steel
Our in-house process chain covers melting through final non-destructive testing, giving full metallurgical control and traceability at every step. No subcontracting for critical process stages.
Key Equipment
Industries Served
Super Austenitic Stainless Steel Applications by Industry
High-PREN super austenitic stainless steel excels wherever standard 316L or duplex grades fail — high chloride concentrations, strongly oxidising acids, and elevated-temperature brine environments.
Oil & Gas
Subsea manifolds, wellhead components, downhole tubing, sour-service risers, and offshore platform piping demand high PREN and resistance to H₂S / CO₂ combined with chlorides.
Chemical Processing
Reactor vessels, heat exchangers, columns, and pump casings handling sulfuric, phosphoric, and hydrochloric acid services benefit from the superior acid resistance of 904L and 20Mo-6.
Seawater Desalination
Evaporator tubes, tube sheets, water boxes, and pump shafts in MSF and SWRO plants require consistent PREN > 40 for long-term chloride pitting resistance.
Pulp & Paper
Bleaching circuit equipment exposed to chlorine dioxide and hypochlorite at elevated temperatures requires the extreme PREN of 654 SMO to prevent intergranular attack and pitting.
FGD Systems
Flue Gas Desulfurisation absorber towers, spray headers, and recirculation pumps contend with dilute sulfuric acid plus chlorides. Super austenitic grades provide extended service life.
Food, Pharma & Medical
Repeated CIP / SIP cycles with chlorinated detergents require pit-free surfaces. Super austenitic grades meet FDA, EC 1935/2004, and USP Class VI requirements.
Our engineering team will recommend the optimal grade and form for your service conditions.
Quality Assurance
Certified Quality at Every Stage
Our ISO 9001-certified quality management system mandates batch-level testing, independent verification, and full documentation before any shipment is released.
EN 10204 Type 3.1 MTC
Every heat includes a third-party witnessed mill test certificate covering certified chemical analysis, mechanical tensile test results, hardness, and heat treatment records, signed by the authorised inspector.
Third-Party Inspection
SGS, Bureau Veritas, Intertek, or customer-nominated inspection agencies can witness chemical testing, dimensional checks, mechanical testing, and final packing at our facility prior to shipment.
Non-Destructive Testing
Ultrasonic testing (UT) per ASTM A388, liquid penetrant testing (PT), positive material identification (PMI) by XRF, and magnetic particle inspection are available per customer specification or project code.
Full Heat Traceability
Every piece is stamped or tagged with heat number and lot number. Traceability is maintained from raw charge materials through melt, rolling, heat treatment, and final inspection to the end customer.
Standard Documentation Package
Global Trust
Trusted by Engineers in 52+ Countries
"We specified 254SMO bar stock for subsea valve bodies. Fushun Metal's material passed our in-house PREN verification and all three-party MTC requirements without exception. Dimensional tolerances were spot-on across a 12-tonne order."
"AL-6XN plate delivered for our FGD absorber project arrived exactly on schedule with Bureau Veritas witness certificates. The technical team responded to our weld procedure queries the same day. Will specify Fushun Metal for our next phase."
"904L tube sheets for a seawater heat exchanger — supplied with 3.1 MTC, ASTM B625 compliance confirmed, and correct ASTM grain-size documentation. Lead time of 18 days from order to port was exceptional. Highly recommend."
Frequently Asked Questions
Super Austenitic Stainless Steel — Technical & Commercial FAQ
Common questions from engineers and procurement teams about super austenitic stainless steel grades, performance, and sourcing from Fushun Metal.
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Request Super Austenitic Stainless Steel Pricing
Submit your grade, form, dimensions, quantity, and delivery requirements. Our technical sales team will respond with a competitive quotation and stock confirmation within 24 business hours.
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