1. Product Attributes
| Alloy Grade |
Incoloy 925 (UNS N09925) |
| Product Type |
Precision Forged Fastener Set |
| Included Components |
Hex Bolts, Hex Nuts, Flat Washers, Hex Studs, Mini Special Threaded Connectors |
| Diameter Range |
M6 - M64 (1/4" - 2-1/2") |
| Thread Standards |
UNC, UNF, BSW, BSP, Metric (M series) |
| Manufacturing Process |
Precision Hot Forging + CNC Machining |
| Applicable Standards |
ASTM B805, NACE MR0175 / ISO 15156, DIN 931/933/934, ASME B18.2.1/B18.2.2 |
| Surface Finish |
Natural Pickled, Mechanical Polished, or Customized as Required |
| Heat Treatment |
Solution Annealed + Age Hardened |
| Density |
8.08 g/cm³ |
2. Material Overview
Incoloy 925 (UNS N09925) is an age-hardenable nickel-iron-chromium alloy with additions of molybdenum, copper, titanium, and aluminum. The alloy's chemical composition is designed to provide a combination of high strength and excellent corrosion resistance. The nickel content (42-46%) is sufficient for protection against chloride-ion stress-corrosion cracking. The nickel, in conjunction with the molybdenum and copper, also gives outstanding resistance to reducing chemicals. The molybdenum aids resistance to pitting and crevice corrosion. The chromium content provides resistance to oxidizing environments. The titanium and aluminum additions cause a strengthening reaction during heat treatment.
Crafted from premium Incoloy 925 via precision hot forging technology, this fastener assembly delivers exceptional sulfide stress cracking resistance, high-temperature mechanical strength, and outstanding anti-corrosion performance in harsh acidic, high-pressure and marine environments. Every component is manufactured to strict dimensional tolerances, ensuring reliable, leak-proof and long-lasting connections for critical industrial equipment.
3. Chemical Composition (Wt. %)
| Element |
Ni |
Cr |
Fe |
Mo |
Cu |
Ti |
Al |
Mn |
Si |
C |
S |
| Content (%) |
42.0 - 46.0 |
19.5 - 22.5 |
≥ 22.0 |
2.5 - 3.5 |
1.5 - 3.0 |
1.9 - 2.4 |
0.1 - 0.5 |
≤ 1.0 |
≤ 0.5 |
≤ 0.03 |
≤ 0.03 |
4. Physical Properties
| Property |
Value |
| Density |
8.08 g/cm³ (0.292 lb/in³) |
| Melting Range |
1311 - 1366°C (2392 - 2490°F) |
| Electrical Resistivity |
1.17 µΩ·m |
| Permeability at 200 Oersteds (15.9 kA/m) |
1.001 |
| Thermal Conductivity |
10.9 W/m·K at 20°C |
| Specific Heat |
435 J/kg·K |
5. Mechanical Properties (Solution-Annealed + Aged)
| Property |
Cold Worked |
Cold Worked + Aged |
| Tensile Strength (min) |
965 MPa (140 ksi) |
≥ 1214 MPa (176 ksi) |
| Yield Strength 0.2% Offset (min) |
724 MPa (105 ksi) |
≥ 830 MPa (120 ksi) |
| Elongation (min 4D) |
≥ 15% |
≥ 13% |
| Reduction of Area (min) |
≥ 35% |
≥ 30% |
| Hardness |
26 - 38 HRC |
35 - 46 HRC |
| Impact Strength (avg at -60°C) |
≥ 35 ft·lb |
≥ 30 ft·lb |
6. Corrosion Resistance Comparison
| Alloy |
UNS |
CPT (°C) in 10% FeCl₃ |
CCT (°C) in 6% FeCl₃ |
Sulfide Stress Cracking (NACE MR0175) |
| Incoloy 925 |
N09925 |
≥ 50 |
≥ 35 |
Pass (No Cracking) |
| Incoloy 825 |
N08825 |
30 - 35 |
15 - 20 |
Conditional |
| Inconel 718 |
N07718 |
25 - 30 |
15 - 20 |
Pass |
| Inconel 625 |
N06625 |
≥ 85 |
≥ 65 |
Pass |
| 316L Stainless |
S31603 |
10 - 15 |
≤ 5 |
Not Recommended |
CPT = Critical Pitting Temperature, CCT = Critical Crevice Temperature. Tests per ASTM G48.
7. Included Components & Specific Application Scenarios
1. External Hex Bolts (Precision Forged)
Core Features: Forged hexagonal head for high torque transmission, full/partial thread options, smooth and burr-free thread surface, uniform grain structure from forging process.
Target Applications:
- Flange joint fastening in high-pressure process piping systems
- Valve body and bonnet assembly for industrial control valves and gate valves
- Structural connections on offshore oil and gas platforms
- High-pressure reactor and heat exchanger shell fastening
- Downhole tool assembly in sour gas well extraction
2. Hex Nuts
Core Features: Precision tapped internal threads, matched thread pitch with corresponding bolts/studs, uniform wall thickness, high tensile and shear strength.
Target Applications:
- Paired with hex bolts/studs for pipeline flange locking and sealing
- Fixation of valve internals and actuator components in chemical processing equipment
- Load-bearing connection nodes in marine engineering facilities
- Pressure vessel and boiler component assembly in power generation systems
3. Flat Washers
Core Features: Uniform thickness, burr-free edge, optimized load-bearing area, smooth surface finish.
Target Applications:
- Disperse clamping load between nut/bolt heads and flange/valve body surfaces to avoid surface abrasion
- Fill minor assembly gaps to improve connection stability and anti-loosening performance
- Used as auxiliary sealing parts in low-pressure corrosive fluid systems
- Protect painted or machined equipment surfaces during tightening operations
4. Hex Studs / Double-End Threaded Studs
Core Features: Double-end full thread design, consistent thread precision, high tensile and fatigue strength.
Target Applications:
- Fixed connection between valve bonnet and valve body for high-pressure industrial valves
- Tube sheet and shell fastening for heat exchangers and pressure vessels
- Flange connections in high-temperature and high-pressure process piping
- Subsea pipeline and subsea production equipment assembly
5. Mini Special Threaded Connectors / Small Specialty Bolts
Core Features: Compact size, fine thread pitch, ultra-high dimensional precision, suitable for small-bore assemblies.
Target Applications:
- Instrumentation tubing and small control valve assembly
- Sampling system and on-line analyzer component fixation
- Small-diameter process piping and accessory installation
- Precision equipment internal connection in chemical analysis systems
8. Key Performance Advantages
- Premium Corrosion Resistance: Resists sulfide stress cracking (SSC), pitting corrosion and crevice corrosion in sour gas, brine and strong acidic environments; fully compliant with NACE MR0175 / ISO 15156 for sour oilfield service.
- High-Temperature Stability: Maintains reliable mechanical strength at continuous operating temperatures up to 650°C (1200°F), ideal for high-temperature process systems.
- Precision Forging Process: Refined internal grain structure, improved fatigue resistance and higher structural integrity compared to standard machined fasteners.
- Strict Dimensional Control: Tight thread tolerance (2A/2B) ensures smooth assembly and consistent clamping force, reducing installation failure and leakage risks.
- Chloride Stress-Corrosion Cracking Resistance: High nickel content (42-46%) provides robust protection in chloride-rich downhole and marine environments.
- Full Traceability: Each batch accompanied by heat number, mill test certificate (EN 10204 3.1), and NACE MR0175 compliance documentation.
9. Product Image Display
10. Supply Forms
| Fastener Type |
Specification / Standard |
| External Hex Bolts |
DIN 931, DIN 933, ASME B18.2.1, M6 - M64, UNC/UNF/Metric |
| Hex Nuts |
DIN 934, ASME B18.2.2, M6 - M64 |
| Flat Washers |
DIN 125, ASME B18.22.1 |
| Hex Studs / Double-End Studs |
DIN 975, ASME B18.31.2, custom lengths available |
| Mini Special Threaded Connectors |
Custom fine thread, per drawing/specification |
11. Typical Applications
| Industry |
Application |
| Oil & Gas |
Upstream drilling equipment, downstream refinery piping, sour gas processing units, wellhead and Christmas tree assembly bolting per API 6A |
| Chemical Processing |
Acid production lines, chemical reactors, corrosive fluid transport systems, high-pressure process piping |
| Marine & Offshore Engineering |
Subsea pipelines, offshore platform structures, seawater treatment equipment, subsea manifold connectors |
| Power Generation |
Fossil power plants, waste heat recovery systems, high-temperature boiler components, pressure vessel assembly |
| Valve & Piping Manufacturing |
Industrial valve assembly, process piping construction, flange connection systems, control valve actuators |
| Precision Instrumentation |
Analytical instruments, sampling systems, small-bore process equipment, on-line analyzer fixation |
12. DINGSCO - Professional Nickel Alloy Manufacturer
DINGSCO is a premier manufacturer and supplier of high-performance nickel alloy products, serving global industries including oil & gas, petrochemical, marine engineering, power generation, and precision instrumentation. With decades of metallurgical expertise, we deliver precision-engineered nickel alloy fasteners, tubing, flanges, and custom components that meet the most demanding international standards.
QUALITY ASSURANCE: Our mission is to provide our customers only with the best quality products. As an ISO 9001:2015, PED 2014/68/EC, and API 6A certified manufacturer, we implement strict Quality Control at every production stage — from raw material inspection to forging, machining, thread testing and final dimensional verification.
SCIENCE AND TECHNOLOGY INNOVATION STRATEGY: We pay close attention to customer needs, implement product innovation, and further leverage the company's full range of product types and material grades to provide customers with one-stop service. Continuous improvement drives our material, process, and equipment optimization programs.
COOPERATION: We are pleased to help others and glad to accept the hand of others. We actively participate in team collaboration and support decision-making. We share our experience with each other and excel at cooperating with different types of colleagues and partners worldwide.
13. Material Selection
DINGSCO offers a comprehensive range of nickel alloys for demanding environments. If Incoloy 925 does not fully meet your specific requirements, we also supply:
| Alloy |
UNS |
Key Feature |
Typical Application |
| Incoloy 825 |
N08825 |
General corrosion resistance |
Chemical processing, acid handling |
| Inconel 718 |
N07718 |
Ultra-high strength up to 650°C |
Aerospace, gas turbine components |
| Inconel 625 |
N06625 |
Superior pitting/crevice resistance |
Seawater, flue gas desulfurization |
| Inconel 725 |
N07725 |
High strength + H₂S resistance |
Sour service downhole equipment |
| Monel K-500 |
N05500 |
Seawater corrosion + high strength |
Marine shafts, pump components |
| Hastelloy C-276 |
N10276 |
Broad chemical resistance |
Severe chemical environments |
14. Customized Products
DINGSCO provides fully customized nickel alloy fastener solutions tailored to your exact specifications:
- Non-Standard Dimensions: Custom diameter, length, thread pitch, and head configurations for special applications
- Special Thread Specifications: ACME, Buttress, BSW, BSP, and custom thread profiles per customer requirements
- Custom Heat Treatment: Tailored solution annealing and aging cycles to meet specific hardness and strength targets
- Surface Finish Options: Natural pickled, mechanical polished, PTFE coating, zinc-nickel plating, or silver plating
- Testing & Certification: 100% UT/PT/PMI available, EN 10204 3.1/3.2 certificates, NACE MR0175 compliance documentation, third-party inspection reports
- Custom Packaging: Individual labeling, barcode traceability, seaworthy packing, and kitting services to match logistics requirements
- Full Material Traceability: Mill Test Certificate (MTC) with heat number traceability from raw material to finished product
Why Choose DINGSCO
- Customization support for non-standard sizes, special thread specifications and custom configurations
- Full material traceability, with Mill Test Certificate (MTC) and third-party inspection reports available
- Full-process quality control covering raw material inspection, forging, machining, thread testing and final dimension check
- Mature export experience serving industrial clients across Europe, North America, Southeast Asia and the Middle East
Payment & Shipping Terms
| Term |
Details |
| Minimum Order Quantity |
Negotiable |
| Price |
Negotiable |
| Packaging Details |
According to Customers' Requests |
| Delivery Time |
(Sample Order) 7 days |
| Payment Terms |
T/T |
| Supply Ability |
Negotiable |
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