AMS 5666 Inconel 625 Bar Stock For Deep-Sea Bolts | H₂S And High Pressure Certified
AMS 5666 Inconel 625 Bar Stock For Deep-Sea Bolts | H₂S And High Pressure Certified suppliers
AMS 5666 Inconel 625 Bar Stock For Deep-Sea Bolts | H₂S And High Pressure Certified factory
AMS 5666 Inconel 625 Bar Stock For Deep-Sea Bolts | H₂S And High Pressure Certified best
AMS 5666 Inconel 625 Bar Stock For Deep-Sea Bolts | H₂S And High Pressure Certified
As a leading supplier and manufacturer in China, GNEE Steel provides cost-effective nickel-based alloy products.
- Send E-mail: ss@gneesteel.com
- Tel: +8615824687445
Why Standard Inconel 625 Alloy Fails in Deep-Sea H₂S Environments
Sticks made of standard ASTM B446 alloy pose safety risks under harsh conditions such as depths exceeding 1500 meters, high-pressure/high-temperature wells, and sulfur-containing (H₂S) environments. The combined effects of high cyclic loading, seawater corrosion, and sulfide stress cracking (SSC) necessitate aerospace-grade reliability-this is why API and NACE standards mandate the use of AMS 5666 alloy for critical fasteners.
Using general-purpose alloy bars as subsea Christmas trees or blowout preventer stud bolts carries the following risks:
⚠️Sulfide stress cracking (due to uncontrolled hardness, >35 HRC)
⚠️Premature fatigue failure (due to non-metallic inclusions)
⚠️Loss of traceability (after 10 years of underwater use, it is impossible to trace substandard batches)
We offer a solution: AMS 5666 alloy bars specifically designed for deep-sea studs.
Get a Quote for Your Subsea Project
AMS 5666 Inconel 625 Bar Stock for Deep-Sea Bolts | H₂S and High Pressure Certified description
GNEE AMS 5666 Inconel 625 Bar Stock for Deep-Sea Oil and Gas Studs
AMS 5666 Inconel 625 (UNS N06625) round bars are a high-quality nickel-chromium superalloy, ideal for deep-sea bolts. They are renowned for their exceptional yield strength, excellent resistance to chloride stress corrosion cracking, and compliance with stringent NACE MR0175/ISO 15156 standards (suitable for hydrogen sulfide and high-pressure acidic environments).
AMS 5666 Inconel 625 Bar Stock – Technical Data Sheet
| Specification | Details |
|---|---|
| Standard | SAE AMS 5666 Rev. X / UNS N06625 |
| Process | VIM + VAR (Double Vacuum Melted) |
| Form | Round Bars (Peeled/Centerless Ground) |
| Diameter Range | 0.5" to 4" (12mm to 100mm) – Custom sizes for stud rolling |
| Delivery Condition | Solution Annealed + Aged (Hardness 30-34 HRC) |
| Key Feature | Meets NACE MR0175 / ISO 15156 for H₂S service |
| Typical Yield Strength | ≥ 550 MPa (80 ksi) – Stable for high preload |
Regarding your key concerns about Inconel 625 submarine bolt rods, our control measures
🔍 1. Metallurgical Purity (Why VIM+VAR?)
Your Concern: Inclusions cause fatigue cracks under cyclic subsea loads.
Our Control: VIM+VAR double melting eliminates oxides and sulfides (ASTM E45 inclusion rating <1.0). Guarantees a clean microstructure for 10⁷ fatigue cycles.
📏 2. Hardness Consistency (NACE MR0175 Compliance)
Your Concern: Localized hard spots (>35 HRC) lead to SSC in H₂S.
Our Control: 100% Hardness testing (3 points per bar end). We deliver 30-34 HRC standard, allowing +1 HRC work hardening during thread rolling while staying compliant.
🛡️ 3. Internal Soundness (Zero Defects)
Your Concern: Hidden porosity or lamination causing a stud to snap during installation.
Our Control: 100% Ultrasonic Testing (UT) per ASTM E2375 Level A. Every inch of the bar is scanned before shipping.
📜 4. Full Traceability (Heat to Part)
Your Concern: If a bolt fails after 5 years, you need to recall the exact batch.
Our Control: Individual bar marking with heat number. Full MTR package including melting certificate, heat treatment chart, UT report, and hardness logs.
Key performance characteristics of AMS 5666 Inconel 625 deep-sea alloy rods
Chemical composition of AMS 5666 Inconel 625 deep-sea rods
| Element | Content (%) | AMS 5666 Requirement | |
|---|---|---|---|
 | Nickel (Ni) | ≥ 58.0 (Balance) | ≥ 58.0 |
| Chromium (Cr) | 20.0 – 23.0 | 20.0 – 23.0 | |
| Molybdenum (Mo) | 8.0 – 10.0 | 8.0 – 10.0 | |
| Niobium (Nb) | 3.15 – 4.15 | 3.15 – 4.15 | |
| Iron (Fe) | ≤ 5.0 | ≤ 5.0 | |
| Titanium (Ti) | ≤ 0.40 | ≤ 0.40 | |
| Aluminum (Al) | ≤ 0.40 | ≤ 0.40 | |
| Carbon (C) | ≤ 0.10 | ≤ 0.10 | |
| Manganese (Mn) | ≤ 0.50 | ≤ 0.50 | |
| Silicon (Si) | ≤ 0.50 | ≤ 0.50 | |
| Phosphorus (P) | ≤ 0.010 | ≤ 0.015 | |
| Sulfur (S) | ≤ 0.005 | ≤ 0.015 | |
| Cobalt (Co) | ≤ 1.0 | ≤ 1.0 | |
| Copper (Cu) | ≤ 0.07 | - |
Gnee Alloy Superalloy Spectrometer Test Records
Room temperature mechanical properties of AMS 5666 625 solution-annealed alloy bars
| Property | AMS 5666 Requirement | Typical Value | Test Standard |
|---|---|---|---|
| Tensile Strength, Ultimate | ≥ 830 MPa (120 ksi) | 900 – 950 MPa | ASTM E8 / AMS 2370 |
| Tensile Strength, Yield (0.2% Offset) | ≥ 415 MPa (60 ksi) | 450 – 500 MPa | ASTM E8 / AMS 2370 |
| Elongation at Break | ≥ 30% | 35 – 45% | ASTM E8 / AMS 2370 |
| Reduction of Area | Not specified | 50 – 60% | ASTM E8 |
| Hardness (Rockwell B) | ≤ 96 HRB | 90 – 95 HRB | ASTM E18 |
| Hardness (Rockwell C) | - | ~22 HRC | ASTM E18 |
| Modulus of Elasticity | ~207 GPa (30.0 × 10⁶ psi) | - | ASTM E111 |
| Poisson's Ratio | 0.29 – 0.30 | - | - |
AMS 5666 Inconel 625 Deep Sea Rod Low Temperature Properties (Deep Sea Critical)
| Temp (°C) | Temp (°F) | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Impact Toughness (J) | Impact Toughness (ft·lb) |
|---|---|---|---|---|---|---|
| 20 (RT) | 68 | ≥ 830 | ≥ 415 | ≥ 30 | ≥ 100 | ≥ 74 |
| 0 | 32 | ~850 | ~430 | ~32 | ~95 | ~70 |
| -20 | -4 | ~860 | ~440 | ~33 | ~90 | ~66 |
| -40 | -40 | ~870 | ~450 | ~34 | ~85 | ~63 |
| -46 | -51 | ~875 | ~455 | ~35 | ≥ 80 | ≥ 59 |
| -54 | -65 | ~880 | ~460 | ~35 | ≥ 60 | ≥ 44 |
| -100 | -148 | ~900 | ~480 | ~36 | ~50 | ~37 |
AMS 5666 Inconel 625 Deep-Sea Bars: Corrosion Resistance
| Environment | Resistance Level | Remarks |
|---|---|---|
| Seawater (Stagnant) | Excellent | No pitting or crevice corrosion with long-term immersion |
| Seawater (Flowing) | Excellent | Withstands flow velocities > 10 m/s, no erosion-corrosion |
| Deep Seawater (High Pressure) | Excellent | Resists high hydrostatic pressure environments |
| Chloride Pitting | Excellent | PRE > 50, excellent pitting resistance |
| Crevice Corrosion | Excellent | Safe for threaded connections, flanges, and crevice areas |
| Chloride Stress Corrosion Cracking (SCC) | Immune | High nickel content provides complete immunity |
| Hydrogen Embrittlement | Excellent | Resistant to cathodic protection induced hydrogen embrittlement |
| Sulfide Stress Corrosion Cracking (SSC) | Excellent | NACE MR0175 certified |
| CO₂ Corrosion (Sweet Service) | Excellent | Resists carbon dioxide corrosion |
| H₂S Corrosion (Sour Service) | Excellent | Resists hydrogen sulfide corrosion, no partial pressure limit |
| Seawater + H₂S Combined | Excellent | Suitable for harsh combined environments |
| Seawater + CO₂ Combined | Excellent | Typical deep sea oil & gas environment |
| Galvanic Corrosion | Noble (cathodic) | Compatible with titanium, super duplex; avoid direct coupling with aluminum, carbon steel |
AMS 5666 Inconel 625 Deep-Sea Bar Pitting Resistance Equivalent (PRE)
PRE formula: PRE = %Cr + 3.3 × %Mo + 16 × %NInconel 625: Cr 20-23% + 3.3 × (8-10% Mo) = 46-56
| Material | PRE Value | Deep Sea Oil & Gas Suitability |
|---|---|---|
| Inconel 625 (AMS 5666) | > 50 | Excellent – suitable for deep water, H₂S service |
| Super Duplex (UNS S32750) | ~40 | Good – suitable for moderate H₂S |
| 316L Stainless Steel | ~25 | Poor – not suitable for deep water |
| Titanium Grade 2 | ~35 | Excellent – not suitable for H₂S service |
Design requirements for Gnee Alloy inconel 625 deep-sea oil and gas round bars
| Requirement | Specification | Significance |
|---|---|---|
| Minimum Tensile Strength | 830 MPa (120 ksi) | Component design basis |
| Minimum Yield Strength | 415 MPa (60 ksi) | Pressure containment design |
| Minimum Elongation | 30% | Ductility for installation |
| Hardness Limit | ≤ 35 HRC (NACE) | SSC resistance for sour service |
| SSC Resistance | NACE MR0175 compliant | H₂S environment suitability |
| Seawater Corrosion | Excellent | Long-term subsea immersion |
| Hydrogen Embrittlement | Resistant | Cathodic protection compatibility |
| Low Temperature Toughness | ≥ 60 J at -54°C | Deep sea cold environment |
| Chloride SCC | Immune | Stress corrosion cracking resistance |
NACE MR0175 / ISO 15156 Compliance
| Parameter | AMS 5666 Inconel 625 |
|---|---|
| Sour Gas Service (H₂S) | Yes – compliant |
| Maximum Hardness | ≤ 35 HRC (annealed condition ~22 HRC) |
| SSC Resistance | Excellent |
| Application | Downhole tools, wellhead equipment, subsea components |
| H₂S Partial Pressure | Any (no limitation) |
| Temperature Range | -60°C to 232°C |
AMS 5666 Inconel 625 Bar heat treatment
| Parameter | Specification | |
|---|---|---|
| Condition | Solution Annealed |
| Temperature | 940 – 1040°C | |
| Time | 1 hour per 25mm thickness | |
| Atmosphere | Controlled atmosphere for bright finish | |
| Cooling | Rapid cool (water or air) |
Recommended Inconel 625 alloy bar size for deep-sea stud rolling
Commonly used stud sizes can be directly machined to the following diameters (thread rolling).
| Finished Stud Size (UN/UNC/Metric) | Recommended Bar Diameter (mm) | Application |
|---|---|---|
| 3/4"-10 UNC | 18.3 mm | Manifold Bolts |
| 1"-8 UNC | 24.2 mm | Christmas Tree Studs (High Demand) |
| 1-1/8"-7 UNC | 27.5 mm | HP/HT Connectors |
| 1-1/4"-7 UNC | 30.5 mm | Wellhead Bolts |
| M20 x 2.5 | 19.2 mm | International Subsea Projects |
| M30 x 3.5 | 28.5 mm | BOP Studs |
Note: We offer peeled bars with a tolerance of h9 – ready for direct use on your CNC rolling mill.
AMS 5581 Inconel 625 Non-destructive Testing (NDT) for Seamless Tubes
| Inspection Item | Inspection Focus | Inspection Pain Point / Requirement |
|---|---|---|
| Hardness (100% inspection or multi-point per bar) | Determines SSC and fatigue resistance; NACE MR0175 mandatory ≤ 35 HRC | Measure 3 points (both ends + middle) per bar; report each value |
| Ultrasonic Testing (UT) | Detects internal inclusions, shrinkage cavities, white spots (fatigue crack sources) | ASTM E2375 Level A, flat-bottom hole equivalent to Φ0.8 mm |
| Room Temperature Tensile (min. 2 per batch) | Verifies yield strength, tensile strength, elongation per AMS 5666 | Additional requirement: Yield ≥ 550 MPa (above standard minimum) |
| Surface NDT (Penetrant / Magnetic Particle) | Detects surface seams, folds, cracks (mandatory before thread rolling) | ASTM E1417 or E3024, Acceptance Class 2 |
| Grain Size | Fine grain (ASTM No. 5 or finer) ensures fatigue performance | Typically requires ASTM No. 5 or finer |
| Inclusion Rating | Controls fatigue sources | ASTM E45, Method A; Sulfides ≤ 1.0, Oxides ≤ 1.5 |
| Aged Microstructure Inspection (optional) | Ensures absence of harmful phases (e.g., excessive δ phase) | SEM or metallographic evaluation |
About Gnee Alloy
Don't risk your high-pressure/high-temperature projects by using ordinary B446 bar stock.
Fill out the form below. You will receive the following within 24 hours:
Best quote for your required diameter and length.
Thread rolling dimension diagram.
Sample MTR for current stock batch.
👉 [ss@gneemetal.com]
Gnee Alloy Inconel 625 certificate
Click to view our professional certificates for Inconel 625 alloy
FAQ
Q: Can I use ASTM B446 instead of AMS 5666 for shallow water?
A: Yes. For <500m, no H₂S, we recommend B446. But for deepwater >1500m with H₂S, only AMS 5666 guarantees NACE MR0175 compliance.
Q: What is the lead time for custom diameters?
A: Standard diameters (18.3mm, 24.2mm, 27.5mm) ship in 2 weeks. Custom diameters require 4 weeks.
Q: Do you test hardness on every single bar?
A: Yes. We perform 100% hardness testing. You receive a report with every bar's values.
Get a Competitive Quote for Inconel 625 Round Bars
China Spot Stock | EN 10204 3.1 MTC | NACE MR0175 | ISO 9001:2015 | Ships to over 50 countries/regions within one week
mailto:ss@gneemetal.com
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