ASTM B444 GR.2 Gr.1 Inconel 625 boiler tube
ASTM B444 GR.2 Gr.1 Inconel 625 boiler tube
ASTM B444 Grade 1 and 2 Inconel 625 boiler tubes are high-strength, corrosion-resistant alloys suitable for demanding applications. The primary difference lies in heat treatment: Grade 1 is annealed for service at temperatures up to 593°C (1100°F), while Grade 2 is solution annealed for use at higher temperatures where creep and rupture resistance are required. Both grades are hydrostatically and electrically tested, meet specific mechanical property requirements, and are available in a variety of forms with a minimum tensile strength of 930 MPa (135,000 psi) and a yield strength of 517 MPa (75,000 psi).
What is the difference between Inconel 625 Grade 1 and Grade 2?
Grade 1 is typically annealed at around 1600°F to 1800°F (approximately 871°C to 982°C) to provide good ductility and corrosion resistance while maintaining higher strength than Grade 2. Grade 2 is heat treated above 2000°F (approximately 1093°C) to enhance creep and stress-rupture resistance while maintaining corrosion resistance.
ASTM B444 UNS N06625 Pipe Specification
| Inconel 625 pipe ASTM Specification | Details |
|---|---|
| Specifications | ASTM B167 / B829 / B517, ASTM B705, ASTM B444, ASTM B474 |
| AMS Standards | AMS 5581, AMS 5599, AMS 5666 |
| Manufacturing Types | Seamless, ERW, Welded, Fabricated, CDW, CDS, DOM, CEW, 100% X-Ray Welded |
| Thickness Range | SCH 5, SCH10, SCH 40, SCH 80, SCH 80S, SCH 160, SCH XXH, SCH XXS, SCH XS |
| Industry Standards | SUS, JIS, AISI, ASTM, GB, DIN, EN |
| Annealed Condition Grades | ASTM B444 Grade 1, ASTM B444 Grade 2, ASME SB444 GR.1, ASME SB444 GR.2 |
| Value-Added Services | Cutting, Beveling, Threading, Destructive and Non-Destructive Testing, Ultrasonic Testing, Draw & Expansion to required sizes and lengths |
| End Types | Plain End, Beveled End, Treaded Alloy 625 Pipe |
| Marking | Specification, Material Grade, Nominal Size, Schedule or Wall Thickness, Manufacturing Method (Seamless/Welded), Heat Number, Manufacturer's Name/Logo |
| Example Marking | ASTM B444 UNS N06625 12" NB SCH 40S SEAMLESS HEAT NO. XXXX |
| Test Certificates | Manufacturer Test Certificate, 100% Radiography Report, DFARS Compliant, EN 10204/3.1B & 3.2 MTCs, Fumigation Certificates, Raw Materials Certificate, Third Party Inspection Report, Laboratory Test Certificate from Govt. Approved Lab, etc. |
| Packaging | Packed in PE Fabric Bundles, ply wooden box wrapped in plastic, or standard seaworthy export packaging |
Chemical Composition of 625 Inconel Pipe
| Element | C | Mn | Si | Fe | S | Cr | Al-Ti | Ni |
|---|---|---|---|---|---|---|---|---|
| min. | ----- | ----- | ----- | ----- | ----- | 20.0 | --- | 58.0 |
| max. | 0.10 | 0.50 | 0.50 | 5.00 | 0.015 | 23.0 | 0.40 | - |
Mechanical Properties of ASTM B444 Inconel 625 Pipe
| Alloy | Tensile Stress (min) | Yield Stress (0.2% Proof, min) | Elongation (% in 50mm, min) | Hardness (max) |
|---|---|---|---|---|
| 625 | 135,000 Psi / 930 MPa | 75,000 Psi / 517 MPa | 42.5 | -- |
Grade-specific information
| Feature | Grade 1 | Grade 2 |
|---|---|---|
| Furnishing Condition | Annealed | Solution Annealed |
| Service Temperature | Up to 593°C (1100°F) | Above 593°C (1100°F) |
| Creep and Rupture Resistance | Lower | Higher |
Grade 1 vs. Grade 2
Grade 1 (Annealed):
Heat Treatment: Typically annealed between 871 and 982 degrees Celsius (1600 and 1800 degrees Fahrenheit).
Service Temperature: Suitable for service temperatures up to 593 degrees Celsius (1100 degrees Fahrenheit).
Features: Provides good ductility and corrosion resistance while maintaining high strength.
Grade 2 (Solution Annealed):
Heat Treatment: Solution annealed above 1093 degrees Celsius (2000 degrees Fahrenheit).
Service Temperature: Suitable for applications above 593 degrees Celsius (1100 degrees Fahrenheit).
Features: In addition to corrosion resistance, it also offers enhanced creep and stress-rupture resistance.
Gnee Steel specializes in the production and sale of various nickel-based alloys, including Nickel 201, Nickel 202, Hastelloy C-276, Hastelloy C-22, Hastelloy B, Hastelloy C-4, Inconel Alloy 600, Inconel 625, Inconel 718, Inconel X-750, Incoloy Alloy 800, Incoloy 800H/HT, Incoloy 825, Monel Alloy 400, Monel K500, and high-temperature alloys. Gnee Steel's products are widely used in aerospace, chemical, electric power, automotive, and nuclear energy applications, and we can provide customized alloy solutions tailored to customer needs. For alloy pricing inquiries or customized alloy solutions, please contact us for a quote at ss@gneemetal.com.
