For engineers in the petrochemical, marine, and nuclear industries, the biggest pain point when using GH3625 is the uncertainty of equivalence. When your blueprints specify the use of ASTM B446 (Inconel 625) alloy, but the supply chain provides a similar product from China, several key questions arise:
Does its chemical purity meet ASTM's stringent vacuum melting requirements?
Can the material pass NACE acid gas environmental audits?
Can the manufacturer provide a globally recognized factory test certificate (MTC) in a format recognized worldwide?
At Gnee Alloy, we are committed to bridging the compliance gap. Our UNS N06625 bars fully comply with international engineering specifications, providing the absolute industrial durability required for your high-pressure and highly corrosive projects.
Click to get an Inconel 625 product quote
ASTM B446 / ASME SB446 Inconel 625 Bars Resistant to High Pressure Corrosion
ASTM B446 / ASME SB446 Inconel 625 Bars Resistant to High Pressure Corrosion
ASTM B446 and ASME SB446 standards specify nickel-chromium-molybdenum alloy 625 (UNS N06625) bars. This material is highly valued for its excellent corrosion resistance under high pressure, high temperature, and severely corrosive environments, and plays an important role in marine, aerospace, and chemical processing industries.
Is Inconel 625 corrosion-resistant?
Inconel 625 is a nickel-chromium-molybdenum alloy with excellent corrosion resistance. It is highly favored in the marine, aerospace, and chemical industries because it resists both general and localized corrosion (such as pitting and crevice corrosion) even in extremely harsh acidic environments.
1. Inconel 625 Round Bar Specifications
| Parameter | Details |
|---|---|
| Grade | Inconel 625 / Alloy 625 |
| UNS No. | N06625 |
| Werkstoff Nr. | 2.4856 |
| ASTM Standard | ASTM B446 / ASME SB446 |
| Aerospace Spec (Bar/Rod) | AMS 5540 (bar, rod and wire - bar/rod specification) |
| Aerospace Spec (Wire) | AMS 5666 (wire only - not applicable to round bar) |
| Welding Wire Spec | AMS 5837 / ERNiCrMo-3 |
| ASME Code | ASME SB446 (Boilers & Pressure Vessels) |
| Diameter (Round Bar) | 3 mm – 600 mm |
| Hex Bar (A/F) | 2 mm – 100 mm |
| Flat Bar Width | 10 mm – 500 mm |
| Length | 100 mm – 6000 mm; cut-to-length on request |
| Forms | Round, Square, Hex, Flat, Forged, Bright, Peeled, CG |
| Certificate | EN 10204 3.1 standard; 3.2 from Bureau Veritas, SGS, Intertek, TÜV on request |
2. Inconel 625 - Chemical Composition (ASTM B446)
| Element | Content (%) | Function | |
|---|---|---|---|
 | Nickel (Ni) | ≥ 58.0 (Balance) | Matrix element; corrosion resistance and high-temperature stability |
| Chromium (Cr) | 20.0 – 23.0 | Oxidation and corrosion resistance | |
| Molybdenum (Mo) | 8.0 – 10.0 | Core solid-solution strengthening; pitting and crevice corrosion resistance | |
| Niobium (Nb) | 3.15 – 4.15 | Solid-solution strengthening; carbide stabilizer | |
| Iron (Fe) | ≤ 5.0 | Residual element | |
| Titanium (Ti) | ≤ 0.40 | Supplementary strengthening | |
| Aluminum (Al) | ≤ 0.40 | Supplementary strengthening | |
| Carbon (C) | ≤ 0.10 | Low carbon for weldability and toughness | |
| Manganese (Mn) | ≤ 0.50 | Deoxidizer | |
| Silicon (Si) | ≤ 0.50 | Deoxidizer | |
| Phosphorus (P) | ≤ 0.015 | Ensures toughness | |
| Sulfur (S) | ≤ 0.015 | Ensures hot workability | |
| Cobalt (Co) | ≤ 1.0 | Residual element |
3. Inconel 625 Round Bar - Mechanical Properties
| Property | Annealed - Grade 1 | Solution Annealed - Grade 2 | Cold-Worked | Unit |
|---|---|---|---|---|
| Tensile Strength (min.) | 827 | 965 | 930 | MPa |
| Yield Strength 0.2 % (min.) | 414 | 552 | 655 | MPa |
| Elongation (min.) | 30 % | 30 % | - | % |
| Hardness | ≤ 220 HB | ≤ 220 HB | - | HB |
| Density | 8.44 g/cm³ | g/cm³ | ||
| Melting Range | 1,290 – 1,350 °C | °C | ||
| Modulus of Elasticity | 207 GPa | GPa | ||
| Thermal Conductivity | 9.8 W/m·K at 21 °C | W/m·K | ||
Request a Quote for Inconel 625 Round Bar
Need Inconel 625 round bars with a complete Material Testing Certificate (MTC)? Gnee Alloy supplies ASTM B446/ASME SB446 materials in diameters of 3–600 mm, with EN 10204 3.1 and 3.2 certifications. Custom lengths are available, and various conditions (annealed, cold-drawn, forged) are offered. In-stock sizes can be shipped quickly.
4. Inconel 625 Equivalent Grades
| Standard | Designation |
|---|---|
| UNS | N06625 |
| Werkstoff Nr. (DIN) | 2.4856 |
| ASME | SB446 |
| AMS (Bar / Rod) | AMS 5540 |
| AMS (Wire) | AMS 5666 |
| AMS (Welding Wire) | AMS 5837 / ERNiCrMo-3 |
| ISO | NW 6625 |
| BS | NA 21 |
| EN | NiCr22Mo9Nb |
| JIS | NCF 625 |
Note: ASTM B446 (rod/bar), ASME SB446 (pressure vessel service), ASTM B443 (sheet/plate/strip) - same alloy, different product form standards. ASTM B444 applies to pipe and tube.
5. Heat Treatment of Inconel 625 Round Bar
Solution Annealing – Minimum temperature 980 °C (1800 °F)
Heat to a minimum of 980 °C, hold for a time proportional to the section thickness, then rapidly air-cool or water-quench. This process completely dissolves carbides and restores corrosion resistance after forming or welding.
Stress Relief – Temperature 870–925 °C, hold for 2–4 hours
Suitable for work-hardened bars that do not age-harden. Relieves residual stress without recrystallization – thus improving low-temperature and fatigue properties. Air-cool after holding.
Quenching/Annealing – 927–1038 °C (1,600–1,900 °F)
Standard range, see heat treatment chart for details. Suitable for hexagonal bars, irregular sections, and round bars.
| Treatment | Temperature Range |
|---|---|
| Quenching / Annealing | 1,600–1,900 °F (927–1,038 °C) |
| Stress Relieving | 1,100–1,600 °F (593–900 °C) |
| Solution Annealing | 2,000–2,200 °F (1,093–1,204 °C) |
Click to download the Inconel 625 alloy PDF file now
6. Inconel 625 Round Bar Diameter & Weight Reference
| Dia. (mm) | Approx. Wt. (kg/m) | Typical Form | Common Applications |
|---|---|---|---|
| 3 – 15 | 0.06 – 1.48 | Cold Drawn / Bright | Fasteners, pins |
| 16 – 50 | 1.68 – 16.74 | Cold Drawn / HR | Valve stems, shafts |
| 51 – 100 | 17.05 – 66.8 | Hot Rolled / Peeled | Pump shafts, pump impellers |
| 101 – 200 | 67.5 – 268.0 | Hot Rolled / Forged | Large valve bodies, flanges |
| 201 – 400 | 268.0 – 1,072 | Forged / Turned | Subsea connectors |
| 401 – 600 | 1,072 – 2,404 | Forged / Turned | Drill collars, large components |
Weight formula: W (kg/m) = (π/4) × d² × 8.44 × 0.001 where d = diameter in mm. Density = 8.44 g/cm³.
Weight Chart - Metric Sizes (kg/m)
| Size | 1″ | 20 mm | 24 mm | 27 mm | 25 mm | 1-1/8″ | 26 mm | 1-1/4″ |
|---|---|---|---|---|---|---|---|---|
| kg/m | 3.097 | 2.047 | 3.054 | 4.049 | 3.087 | 5.003 | 4.017 | 6.035 |
| Size | 30 mm | 1-3/8″ | 32 mm | 36 mm | 35 mm | 38 mm | 7/8″ | 22 mm |
|---|---|---|---|---|---|---|---|---|
| kg/m | 5.055 | 7.055 | 6.031 | 7.100 | 7.055 | 8.090 | 3.004 | 2.098 |
Weight Chart - Imperial Sizes (kg/ft)
| Size | 1/8″ | 3/16″ | 7/32″ | 5/16″ | 3/8″ | 7/16″ | 1/2″ | 5/8″ | 3/4″ | 1″ |
|---|---|---|---|---|---|---|---|---|---|---|
| kg/ft | 0.019 | 0.043 | 0.058 | 0.118 | 0.170 | 0.232 | - | - | - | - |
Contact us to customize Inconel 625 products to fit your project dimensions
7. ASTM B446 UNS N06625 Rod Dimensional Tolerances
| OD (mm) | H5 | H6 | H7 | H8 | H9 | H10 | H11 | H12 |
|---|---|---|---|---|---|---|---|---|
| Over 3 – 6 | +0.005/0 | +0.008/0 | +0.012/0 | +0.018/0 | +0.030/0 | +0.048/0 | +0.075/0 | +0.120/0 |
| Over 6 – 10 | +0.006/0 | +0.009/0 | +0.015/0 | +0.022/0 | +0.036/0 | +0.058/0 | +0.090/0 | +0.150/0 |
| Over 10 – 18 | +0.008/0 | +0.011/0 | +0.018/0 | +0.027/0 | +0.043/0 | +0.070/0 | +0.110/0 | +0.180/0 |
| Over 18 – 30 | +0.009/0 | +0.013/0 | +0.021/0 | +0.033/0 | +0.052/0 | +0.084/0 | +0.130/0 | +0.210/0 |
| Over 30 – 50 | +0.011/0 | +0.016/0 | +0.025/0 | +0.039/0 | +0.062/0 | +0.100/0 | +0.160/0 | +0.250/0 |
| Over 50 – 80 | +0.013/0 | +0.019/0 | +0.030/0 | +0.046/0 | +0.074/0 | +0.120/0 | +0.190/0 | +0.300/0 |
| Over 80 – 120 | +0.015/0 | +0.022/0 | +0.035/0 | +0.054/0 | +0.087/0 | +0.140/0 | +0.220/0 | +0.350/0 |
| Over 120 – 180 | +0.018/0 | +0.025/0 | +0.040/0 | +0.063/0 | +0.100/0 | +0.160/0 | +0.250/0 | +0.400/0 |
| Over 180 – 250 | +0.020/0 | +0.029/0 | +0.046/0 | +0.072/0 | +0.115/0 | +0.185/0 | +0.290/0 | +0.460/0 |
8. Applications of Inconel 625 Round Bars
A key characteristic of Inconel 625 alloy is its near-immunity to chloride stress corrosion cracking, making it a preferred material for marine, seabed, and acidic gas environments-a distinction from Inconel 718 (used in aerospace rotating components) and 600 (used in high-temperature furnaces).
Marine and Seabed Engineering
Acidic Gas Environments (NACE MR0175)
Acidic and Corrosive Environments
Aerospace
Reactor Components
Liquefied Natural Gas and Cryogenic Environments
Defense and Submarines
Contact our professionals to recommend the right alloy for your project
9. Gnee Alloy Inconel 625 Alloy Test Certificates and Documents
Click to view our professional certificates for Inconel 625 alloy
10. Inconel 625 Round Bar Price List
| Grade | Diameter Range | Est. Price (INR/kg) |
|---|---|---|
| Inconel 625 (UNS N06625) | 3 – 30 mm | £3,800 – £4,200 |
| Inconel 625 (UNS N06625) | 30 – 100 mm | £3,900 – £4,400 |
| Inconel 625 (UNS N06625) | 100 – 250 mm | £4,200 – £4,800 |
| Inconel 625 (UNS N06625) | > 250 mm (forged) | On request |
Prices are indicative and subject to change based on LME nickel prices and alloy surcharges. Contact Gnee Alloy for a current quotation based on your exact diameter, quantity, condition, and certificate requirement.
Contact us now for the latest export prices of Inconel 625 in 2026
Why Choose Gnee as Your Nickel-Based Alloy Supplier
✅️Direct Factory Price: Eliminate the 15-20% trading markup and secure original mill rates.
✅️Wholesale Inventory: Massive stock of forged and rolled rods (10mm to 300mm) ready for Fast Global Shipping.
✅️Custom Fabrication: We provide precision Cut-to-Length services and specialized thermal treatment to match your assembly line blueprints.
✅️Total Traceability: Every bar is marked with its heat number, linked directly to its digital MTC audit trail.
Gnee Alloy Inconel 625 Certificate
📦 Packaging and Shipping
All Nickel Based Alloy products are packaged using the following methods:
Wooden pallets or crates
Moisture-proof packaging
Labels with furnace number, standard, and size labels
Shipped worldwide by sea, air, or express
Gnee Alloy Alloy 625 Product Packing
⚒️Gnee Alloy Production Line Equipment and Product Testing
Contact us for the latest export price quote for 625 Alloy
FAQ
Q1: Can GH3625 really replace ASTM B446 Inconel 625?
A: Yes. GH3625 is the equivalent grade in Chinese drawings used to represent the same metallurgical system as UNS N06625. We provide the necessary supporting documentation to demonstrate the consistency of its chemical composition and mechanical properties, ensuring your audit is risk-free.
Q2: How do you guarantee the Pitting Resistance Equivalent Number (PREN)?
A: We calculate the PREN (Cr + 3.3Mo + 16N) for every heat. Our VIM+VAR process allows us to keep Chromium and Molybdenum at the high end of the range, consistently hitting a PREN of 48-52.
Q3: Do you offer trial orders for material validation?
A: Absolutely. As a Reliable Supplier, we support Innovation. We offer Flexible MOQs on our in-stock inventory for laboratory testing and prototype validation.
Q4: Can you provide bright ground rods for automatic feeders?
A: Yes. We specialize in Precision Ground bars with an h9 tolerance and mirror finish (Ra ≤ 0.4μm), ensuring zero vibration and zero bar-feeder interference.
