In high-pressure chemical reactors, aerospace fuel systems, and marine manifolds, piping is among the most vulnerable components. For purchasing managers and quality engineers, the biggest challenges when sourcing Inconel 625 (UNS N06625) seamless steel pipe include:
Wall eccentricity (uneven wall thickness): Poor concentricity creates "weak points," leading to localized stress concentrations and potentially catastrophic pipe bursts under high-pressure cycling.
Internal pitting risk: Inconsistent inner diameter (ID) surface integrity can become the starting point for localized corrosion and pinhole leaks.
Insufficient traceability: Sourcing from uncertified traders who cannot provide a certified EN 10204 3.1 factory test certificate (MTC).
At Gnee Alloy, we eliminate these risks. As a professional manufacturer of Inconel 625 seamless steel pipe, we solve these technical challenges through a sophisticated multi-stage cold-drawing process and 100% quality assurance.
Click here for an Inconel 625 product quote
ASTM B444 Inconel 625 (UNS N06625) High-Pressure Corrosion-Resistant Seamless Pipe Standard
ASTM B444 standard specifies seamless nickel-chromium-molybdenum-niobium alloy (UNS N06625 / Inconel 625) tubing. It is the authoritative standard for high-pressure, extreme-temperature environments and is suitable for products requiring extremely high resistance to oxidation, pitting corrosion, and stress corrosion cracking.
What is ASTM B444 UNS N06625 material?
ASTM B444 UNS N06625 Grade 1 steel pipe is supplied in the annealed condition, while Grade 2 steel pipe is supplied in the solution-annealed condition. 2.4856 Alloy 625 steel pipe (also known as UNS N06625) possesses many superior properties. One of the most critical properties is its corrosion resistance.
| GRADE | UNS | GB | JIS | ISO | DIN/EN | GOST | |
| ISC | NEW | ||||||
| Inconel 625 | N06625 | - | NS336 | NCF625 | - | 2.4856 | - |
2. Chemical Composition of UNS N06625 Pipe (wt.%)
| Grade | Condition | Tensile Strength (min) | Yield Strength 0.2% (min) | Elongation (min) |
|---|---|---|---|---|
| Grade 1 | Annealed | ≥ 827 MPa (120 ksi) | ≥ 414 MPa (60 ksi) | ≥ 30% |
| Grade 2 | Solution Annealed + Cold Worked | ≥ 827 MPa (120 ksi) | ≥ 689 MPa (100 ksi) | ≥ 30% |
Click here to download the Inconel 625 alloy PDF file
4. High-Temperature Creep & Rupture Strength (Grade 1, Annealed)
| Temperature | Stress for 100,000 hr Rupture (Typical) | Reference |
|---|---|---|
| 500°C (932°F) | ~450 MPa (65 ksi) | ASME BPVC Section II, Part D |
| 600°C (1112°F) | ~210 MPa (30 ksi) | ASME BPVC Section II, Part D |
| 700°C (1292°F) | ~90 MPa (13 ksi) | ASME BPVC Section II, Part D |
5. Dimensions of UNS N06625 Pipe
|
Nominal Thickness (in) |
Pipe Size (in) |
External Diameter (in) |
Internal Diameter (in) |
Weight (lb/ft) |
Threads per inch |
|---|---|---|---|---|---|
|
0.068 |
1/8 |
0.405 |
0.269 |
0.24 |
27 |
|
0.088 |
1/4 |
0.540 |
0.364 |
0.42 |
18 |
|
0.091 |
3/8 |
0.675 |
0.493 |
0.57 |
18 |
|
0.109 |
1/2 |
0.840 |
0.622 |
0.85 |
14 |
|
0.113 |
3/4 |
1.050 |
0.824 |
1.13 |
14 |
|
0.133 |
1 |
1.315 |
1.049 |
1.68 |
11 ½ |
|
0.140 |
1 1/4 |
1.660 |
1.380 |
2.27 |
11 ½ |
|
0.145 |
1 1/2 |
1.900 |
1.610 |
2.72 |
11 ½ |
|
0.154 |
2 |
2.375 |
2.067 |
3.65 |
11 ½ |
|
0.203 |
2 1/2 |
2.875 |
2.469 |
5.79 |
8 |
|
0.216 |
3 |
3.500 |
3.068 |
7.58 |
8 |
|
0.226 |
3 1/2 |
4.000 |
3.548 |
9.11 |
8 |
|
0.237 |
4 |
4.500 |
4.026 |
10.79 |
8 |
|
0.258 |
5 |
5.563 |
5.047 |
14.62 |
8 |
|
0.280 |
6 |
6.625 |
6.065 |
18.97 |
8 |
|
0.322 |
8 |
8.625 |
7.981 |
28.55 |
8 |
|
0.365 |
10 |
10.750 |
10.020 |
40.48 |
8 |
|
0.406 |
12 |
12.750 |
11.938 |
53.57 |
8 |
|
0.437 |
14 |
14.000 |
13.126 |
63.39 |
8 |
|
0.500 |
16 |
16.000 |
15.000 |
82.77 |
8 |
|
0.562 |
18 |
18.000 |
16.876 |
104.67 |
8 |
|
0.593 |
20 |
20.000 |
18.814 |
123.01 |
8 |
|
0.687 |
24 |
24.000 |
22.626 |
171.29 |
8 |
5. Pressure Rating of Inconel 625 Tubing
|
OD (in) |
Wall Thickness: 0.035" |
Wall Thickness: 0.049" |
Wall Thickness: 0.065" |
|---|---|---|---|
|
1/4" |
4,800 |
7,000 |
9,500 |
|
3/8" |
3,100 |
4,400 |
6,100 |
|
1/2" |
2,300 |
3,200 |
4,400 |
|
3/4" |
- |
2,200 |
3,000 |
|
1" |
- |
- |
2,200 |
Pressure Rating Clarification (Based on ASME B31.3)
| Temperature (°C) | Temperature (°F) | Derating Factor (Relative to 38°C / 100°F) |
|---|---|---|
| ≤ 38 | ≤ 100 | 1.00 |
| 200 | 392 | 0.92 |
| 400 | 752 | 0.78 |
| 500 | 932 | 0.58 |
| 600 | 1112 | 0.35 |
6. Inconel 625 Pipe Weight Chart (per Meter)
|
NPS (in) |
OD (mm) |
Schedule 40 ( |
Schedule 80 ( |
|---|---|---|---|
|
1/2" |
21.3 |
1.27 |
1.62 |
|
3/4" |
26.7 |
1.69 |
2.20 |
|
1" |
33.4 |
2.50 |
3.24 |
|
1 1/2" |
48.3 |
4.05 |
5.41 |
|
2" |
60.3 |
5.44 |
7.48 |
|
3" |
88.9 |
11.29 |
15.27 |
|
4" |
114.3 |
16.07 |
22.32 |
|
6" |
168.3 |
28.26 |
42.56 |
|
8" |
219.1 |
42.55 |
64.63 |
Contact us to customize Inconel 625 products to fit your project dimensions
7. Available Types of Inconel 625 Pipes & Tubes
Click here to view Gnee Alloy Inconel 625 Pipe inventory list
8. Inconel 625 100% Non-destructive Testing
As a Tier 1 manufacturer, Gnee Alloy ensures zero defects in the internal microstructure of our products through rigorous non-destructive testing (NDT) processes.
Ultrasonic Testing (UT): Detects internal voids, longitudinal cracks, and wall thickness variations.
Eddy Current Testing (ET): Scans for surface and sub-surface defects to ensure flawless integrity.
Hydrostatic Testing: Verified to withstand internal pressures according to ASME B31.3.
Total Traceability: Every meter of pipe is heat-number stamped and matched to its original heat analysis.
Why Choose Gnee as Your Nickel-Based Alloy Supplier
✅️Direct Factory Pricing: Eliminate the 15-20% trading markup and buy original mill material.
✅️Fast Global Shipping: Optimized logistics to minimize lead times for international maintenance and production runs.
✅️NACE MR0175 Compliance: Specifically heat-treated for Sour Gas (H2S) environments.
✅️Custom Fabrication: We offer precision cutting, beveling, and bending to match your blueprints.
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 Inconel 625 Product Packing
Contact us for the latest export price quote for 625 alloy in 2026.
FAQ
Q1: Is your GH3625 pipe interchangeable with Inconel 625?
A: Absolutely. GH3625 is the technical equivalent designation used within the GB/T system for the metallurgical system known globally as Inconel 625 (UNS N06625). They share identical chemistry and mechanical parity.
Q2: Can you provide bright annealed tubing for precision instruments?
A: Yes. Our Bright Annealing (BA) process ensures the ID is free from oxidation scale, making it ideal for precision sensors where debris contamination would cause system failure.
Q3: Does the ASTM B444 standard cover both Grade 1 and Grade 2?
A: Yes. We supply both Grade 1 (Annealed) for general corrosion and Grade 2 (Solution Annealed) for higher fatigue strength and creep resistance at temperatures above 600°C.
Q4: Do you offer bulk discounts for petrochemical refinery overhauls?
A: Yes. We support large-scale energy infrastructure projects with tiered Wholesale Pricing and dedicated inventory reserves.
