Stainless pipe fitting,stainless fitting,duplex stainless,31803,32750,32760,we are one of largest sour service stainless fitting supplier according to ISO 10156.
Key Specifications: UNS N06601 | ASTM B163 / B166 / B167 | Max Service Temp: 1205°C | Density: 8.11 g/cm³ | Tensile Strength: ≥690 MPa | Ni-Cr-Fe-Al Formulation
1. Material Overview: The Upgraded Alumina-Forming Heat-Resistant Alloy
Alloy 601 (UNS N06601) is a high-performance solid-solution strengthened nickel-chromium-iron alloy, engineered as a significant upgrade over conventional Alloy 600. Manufactured in full compliance with ASTM B163, B166, B167 and corresponding ASME SB specifications, UNS N06601 incorporates a deliberate aluminum addition to deliver exceptional high-temperature oxidation resistance and thermal cycling stability, while retaining excellent aqueous corrosion resistance for multi-service environments.
Featuring an optimized Ni-Cr-Fe-Al formulation, Alloy 601 forms a dense, tightly adherent alumina-chromia protective scale. This unique oxide layer resists spalling under repeated heating and cooling cycles, solving the premature failure problems typical of conventional heat-resistant stainless steels like 310S. The alloy maintains reliable structural integrity at continuous operating temperatures up to 1205°C, with outstanding resistance to carburization, mild sulfidation and thermal fatigue.
2. Standard Chemical Composition (wt%): The Aluminum Advantage
The controlled chemistry of UNS N06601 ensures stable high-temperature performance and oxidation resistance. The intentional aluminum addition (1.00-1.70%) is the core upgrade, enabling superior anti-spalling protection.
| Element | Ni | Cr | Al | Fe | C (max) | Si (max) | Mn (max) | Cu (max) |
|---|---|---|---|---|---|---|---|---|
| Specification | 58.00–63.00 | 21.00–25.00 | 1.00–1.70 | Balance | 0.10 | 0.50 | 1.00 | 1.00 |
P max 0.030, S max 0.015. The high nickel content provides immunity to chloride stress corrosion cracking, while balanced iron ensures good hot workability and welding ductility.
3. Heat Treatment & Mechanical Properties
3.1 Solution Annealing Process
All Alloy 601 products are supplied in the solution-annealed condition. The standard heat treatment at 1015°C–1120°C followed by rapid air cooling or water quenching dissolves intermetallic precipitates, homogenizes the austenitic microstructure, and maximizes ductility and creep rupture resistance. Each batch is supported by complete heat treatment records and PMI spectral reports.
3.2 Room-Temperature Mechanical Properties (Annealed)
- Tensile Strength: ≥690 MPa
- Yield Strength (0.2% offset): ≥300 MPa
- Elongation: ≥35%
- Brinell Hardness: ≤215 HB
3.3 Physical & High-Temperature Characteristics
Density: 8.11 g/cm³ | Expansion Coefficient (20–1000°C): 14.5×10⁻⁶/°C. The alloy’s dimensional stability and resistance to thermal fatigue make it suitable for prolonged high-temperature cycling. Maximum continuous oxidizing service temperature: 1205°C.
4. Core Performance Advantages of UNS N06601
4.1 Exceptional Cyclic Oxidation Resistance
Synergistic aluminum and chromium protection forms a self-repairing, non-spalling composite oxide scale. Under frequent heating-cooling cycles, Alloy 601 significantly outperforms Alloy 600 and 310S stainless steel, making it ideal for cyclic thermal processes.
4.2 Excellent Carburization & Mild Sulfidation Resistance
The alloy effectively blocks carbon infiltration in carburizing/nitriding atmospheres, preventing matrix embrittlement. It also demonstrates reliable tolerance to low-concentration sulfur-containing flue gases in waste incineration and biomass combustion environments.
4.3 Immunity to Chloride Stress Corrosion Cracking
The high-nickel austenitic matrix is immune to chloride-induced stress corrosion cracking common in 300-series stainless steels. It provides stable corrosion resistance in alkaline solutions, fresh water, atmospheric exposure, and mild brine media, adapting to combined high-temperature and corrosive service.
4.4 Outstanding Thermal Fatigue & Creep Performance
Optimized composition resists grain coarsening, thermal fatigue cracking, and structural deformation after thousands of hours of ultra-high-temperature operation, ensuring long service life for continuous-cycle furnace equipment.
4.5 Reliable Fabrication & Weldability
In the solution-annealed state, UNS N06601 exhibits excellent hot forging, cold bending, stamping, and machining characteristics. It is easily welded via GTAW, GMAW, and SMAW processes with matched nickel-based consumables, ensuring low cracking sensitivity and stable forming quality.
5. UNS N06601 Product Range & Dimensions
We supply a full range of Alloy 601 products manufactured to ASTM/ASME standards for high-temperature and corrosion-resistant systems:
- Forged Pipe Fittings: Seamless elbows, tees, reducers, caps. Sizes 1/2″ – 48″, SCH10 – SCH160. Custom heavy-wall configurations available.
- Seamless Pipes & Tubes: OD 16mm – 720mm, WT 3mm – 90mm. Hot-finished and cold-drawn, cut-to-length service.
- Plates, Sheets & Bars: Thick plates, thin sheets, round and flat bars for forging blanks and precision CNC machining.
- High-Temperature Flanges: WN, SO, blind flanges and custom furnace forgings. Threaded NPT flanges per ASME B16.5 also available.
6. Key Application Fields
- Industrial Heat Treatment Furnaces: Radiant tubes, muffles, rollers, baskets, carburizing/nitriding fixtures.
- Petrochemical & Refining: Reformer tubes, cracking furnace internals, high-temperature heat exchanger tubes.
- Thermal Power & Waste-to-Energy: Waste incineration parts, flue gas ducts, superheater components.
- Aerospace & Gas Turbine: Combustion liners, transition ducts, thermal shielding parts.
- Chemical Processing: Caustic evaporation equipment, high-temperature reaction vessel internals, corrosion-resistant piping.
7. Quality Assurance & Certified Mill Test Reports
All Alloy 601 (UNS N06601) products are manufactured under our ISO 9001 quality system. Inspection workflow covers: raw material spectral recheck → hot forming & solution annealing → mechanical testing → UT/MT non-destructive testing → dimensional verification → laser marking & vacuum packaging. Every shipment is accompanied by an EN 10204 3.1 mill test certificate. Permanent laser marking ensures full traceability with grade, heat number, and size.
Related resources: Browse our full range of nickel alloy pipe fittings & seamless tubes, or learn more about our manufacturing capabilities on the C&N YouTube channel for product testing and factory updates.
