- E-mail: [email protected]
- WhatsApp: +86 18533346372
Home > Products > Incoloy bar > Incoloy 25-6Mo/N08926/W.Nr. 1.4529/Alloy 25-6Mo bar
Incoloy 25-6Mo bar, corresponding to UNS N08926 and W.Nr. 1.4529, and commonly referred to as Alloy 25-6Mo or simply Alloy 926, is a super-austenitic …
Incoloy 25-6Mo bar, corresponding to UNS N08926 and W.Nr. 1.4529, and commonly referred to as Alloy 25-6Mo or simply Alloy 926, is a super-austenitic stainless steel containing high levels of chromium, nickel, molybdenum (6%), and nitrogen. This bar stock form is engineered to provide exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking in aggressive chloride-containing environments such as seawater, brines, and chemical process streams. It represents a high-performance, cost-effective alternative to nickel-based alloys for many demanding applications in offshore, marine, and chemical industries.
Incoloy 25-6Mo is a nitrogen-strengthened, high-molybdenum austenitic alloy designed to bridge the gap between standard stainless steels and nickel-based corrosion-resistant alloys. With a Pitting Resistance Equivalent Number (PREN) typically over 45, it offers superior localized corrosion resistance. The “25-6Mo” designation highlights its approximate nickel (25%) and molybdenum (6%) content. The bar stock is ideal for machining critical components like pump shafts, valve stems, fasteners, and fittings where failure from chloride attack is a primary concern.
The outstanding corrosion resistance of Incoloy 25-6Mo bar is a direct result of its high alloy content and balanced composition. Supplied by Shanghai NC Metal Materials Co., Ltd., the bar stock meets strict specifications to ensure consistent performance in severe environments.
| Element | Percentage (%) – Typical Range | Primary Function in the Alloy |
|---|---|---|
| Nickel (Ni) | 24.0 – 26.0 | Stabilizes the austenitic structure, provides resistance to stress corrosion cracking, and enhances overall corrosion resistance. |
| Chromium (Cr) | 19.0 – 21.0 | Provides resistance to oxidizing environments and forms a stable passive film. |
| Molybdenum (Mo) | 6.0 – 7.0 | Key element for resisting pitting and crevice corrosion in chloride solutions; dramatically increases the PREN value. |
| Nitrogen (N) | 0.15 – 0.25 | Powerful austenite stabilizer and solid-solution strengthener; significantly increases yield strength and further improves pitting resistance. |
| Copper (Cu) | 0.5 – 1.5 | Enhances resistance to reducing acids, particularly sulfuric acid. |
| Iron (Fe) | Balance | Base element of the alloy matrix. |
| Manganese (Mn) | 2.0 max | Promotes nitrogen solubility and aids in austenite stability. |
| Silicon (Si) | 0.5 max | Residual element. |
| Carbon (C) | 0.02 max | Kept very low to prevent sensitization during welding and to maintain corrosion resistance. |
| Phosphorus (P) | 0.03 max | Impurity control. |
| Sulfur (S) | 0.01 max | Impurity control; kept low for optimal corrosion resistance. |
Incoloy 25-6Mo bar offers high strength, especially yield strength, due to nitrogen alloying, along with good ductility and toughness. It is supplied in the solution-annealed condition.
| Mechanical Property | Typical Value at Room Temperature (Annealed) | Key Characteristic |
|---|---|---|
| Tensile Strength | 650 – 850 MPa (94 – 123 ksi) | High tensile strength allows for design with thinner sections. |
| Yield Strength (0.2% Offset) | ≥ 300 MPa (44 ksi) | Approximately 50% higher than Type 316L stainless steel, due to nitrogen strengthening. |
| Elongation in 2 inches (50mm) | ≥ 35% | Good ductility for forming and fabrication. |
| Hardness (Rockwell B) | 95 – 110 HRB | – |
| Impact Toughness (Charpy V-notch) | Typically > 100 J at -40°C (-40°F) | Excellent low-temperature toughness. |
The physical properties of Alloy 25-6Mo bar are important for thermal and mechanical design in corrosive service environments.
| Physical Property | Value at Room Temperature (20°C / 68°F) | Notes / Condition |
|---|---|---|
| Density | 8.1 g/cm³ (0.293 lb/in³) | – |
| Melting Range | 1320 – 1390°C (2410 – 2535°F) | – |
| Specific Heat | 500 J/kg·°C (0.119 BTU/lb·°F) | At 100°C |
| Thermal Conductivity | 12.0 W/m·K (83.2 BTU·in/hr·ft²·°F) | At 100°C |
| Mean Coefficient of Thermal Expansion | 15.0 μm/m·°C (8.3 μin/in·°F) | 20-100°C (68-212°F) |
| Electrical Resistivity | 0.85 μΩ·m (33.5 μΩ·in) | At 20°C |
| Modulus of Elasticity (Tensile) | 200 GPa (29.0 x 10^6 psi) | At 20°C |
Shanghai NC Metal Materials Co., Ltd. supplies Incoloy 25-6Mo bar in various forms suitable for marine, offshore, and chemical processing equipment.
| Product Form | Standard Size Range | Key Standard Specifications | Common Supply Conditions |
|---|---|---|---|
| Round Bar (Hot Rolled/Forged) | 10mm (0.4″) to 300mm (12″) Diameter | ASTM B649 (UNS N08926), ASME SB-649, DIN 17744 (W.Nr. 1.4529), NACE MR0175/ISO 15156 | Solution Annealed (typically 1150-1180°C water quench) |
| Hexagonal Bar | 10mm to 80mm Across Flats | ASTM B649, DIN 17744 | Solution Annealed |
| Square Bar | 10mm to 80mm Width | ASTM B649 | Solution Annealed |
| Cold Finished Bar (Drawn/Ground) | 5mm to 120mm Diameter | ASTM B649 (cold drawn) | Solution Annealed, Cold Drawn & Stress-Relieved |
| Forging Billet | 150mm to 400mm Diameter | ASTM B564 (Forgings), Customer specs | As-Forged, Solution Annealed |
Machined components from Incoloy 25-6Mo bar are critical in environments with high chloride concentrations: Marine & Offshore: Shafts, pumps, valves, and fasteners for seawater cooling systems, desalination plants (MED, MSF, RO), offshore platform components, and submarine fittings. Oil & Gas: Tubing, fittings, downhole tools, and Christmas tree components for sour service (H2S/CO2/Cl-) when qualified to NACE MR0175 standards. Chemical Processing: Equipment for handling chloride-containing process streams, dilute sulfuric acid, and organic acids in evaporators and reactors. Pollution Control: Components in flue gas desulfurization (FGD) scrubbers and effluent treatment plants exposed to chloride-laden acids.
Incoloy 25-6Mo offers exceptional resistance to localized corrosion. Its very high PREN (typically >45) ensures excellent resistance to pitting and crevice corrosion, with high Critical Pitting Temperature (CPT) and Critical Crevice Temperature (CCT) in chloride solutions, often outperforming duplex stainless steels. It provides superior resistance to chloride stress corrosion cracking (SCC). The alloy also shows good general corrosion resistance in oxidizing and mildly reducing acids, including sulfuric, phosphoric, and formic acids. Its performance in seawater and brackish water is outstanding, making it a premier material for critical seawater-handling components.
Machining Incoloy 25-6Mo bar requires techniques for high-strength, work-hardening austenitic alloys. Its higher strength and work-hardening rate compared to standard stainless steels necessitate: rigid machine tools; sharp carbide cutting tools with positive rake angles; moderate speeds and feeds; and ample coolant flow to control heat and work hardening. Machinability is lower than that of 316L but is manageable with proper tooling and parameters.
Alloy 25-6Mo is weldable using common processes like Gas Tungsten Arc Welding (GTAW/TIG) and Shielded Metal Arc Welding (SMAW). Due to its high molybdenum content, it is essential to use matching or over-alloyed filler metals (e.g., ERNiCrMo-3, ERNiCrMo-4, or a dedicated 6Mo-type filler) to maintain corrosion resistance in the weld metal. Its low carbon content minimizes sensitization risk. However, for optimal performance in aggressive environments, especially for heavy sections, a post-weld solution anneal is recommended to fully restore the corrosion resistance of the heat-affected zone.
The price of Incoloy 25-6Mo bar from Shanghai NC Metal Materials Co., Ltd. is influenced by its high content of nickel, molybdenum, and nitrogen, positioning it as a premium stainless alloy with significant cost savings over nickel-based alternatives for many applications.
| Pricing Factor | Impact on Reference Price | Procurement Guidance |
|---|---|---|
| High-Alloy Content | Significant nickel (~25%) and high molybdenum (~6.5%) content are the primary cost drivers. Nitrogen addition also contributes to processing costs. | Alloy 25-6Mo is often a cost-effective alternative to nickel-based alloys like Hastelloy C-276 for many seawater and chloride services, offering a favorable balance of performance and cost. |
| Manufacturing and Quality Control | The requirement for very low carbon and sulfur, along with precise nitrogen control, requires specialized melting practices (AOD/VOD), adding to the base cost. | Ensure the supplier’s Mill Test Report confirms the tight composition limits, especially for nitrogen, which is critical for achieving the specified mechanical properties. |
| Industry Certification | Bar supplied with NACE MR0175/ISO 15156 certification for sour service or with specific pitting corrosion test data (e.g., ASTM G48) may carry a premium. | For offshore and oil & gas applications, NACE certification is often mandatory and should be specified upfront. |
| Form, Size, and Testing | Cold-finished precision bars and large forging stock are more expensive. Additional testing like pitting corrosion tests or PMI adds cost. | For standard components, hot-rolled bar is sufficient. Clearly define if any special testing beyond the standard MTR is required for project approval. |
We are factory wholesale price, and the prices are lower than 95% of suppliers. Our professional quotation will help you with your project. Expecting our long-term cooperation. ）
English English 
Korean
Arabic
Spanish
German
Portuguese
French
Russian
Italian
Vietnamese
