Inconel® Tube: High-Performance Nickel Alloy for Extreme Temperature and Corrosion Challenges
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In an offshore oil platform off Norway, Inconel 625 tubing in sour gas service cracked under hydrogen embrittlement, leading to leaks and shutdowns amid high-pressure H2S exposure. Such failures underscore the demands on materials in oil & gas, where Inconel® tubes provide unmatched oxidation and stress-corrosion cracking resistance up to 980°C.
Specifications and Standards
Inconel® tubes adhere to ASTM B163/B167 (seamless), B516/B517 (welded) for grades like UNS N06625, with ASME SB equivalents for pressure applications. DIN 2.4856 ensures international compatibility, including NDT, flattening, and hydrostatic tests for marine and power sectors.
Specifications by Grade – Pipe and tube
A specification is written for a product form. The standards below are the ones that cover pipe and tube; the plate, bar and tube specifications for these grades are different documents and are listed on their own pages.
| Grade | UNS | Pipe and tube specification |
|---|---|---|
| 600 | N06600 | ASTM B167 |
| 601 | N06601 | ASTM B167 |
| 617 | N06617 | ASTM B167 / B546 |
| 625 | N06625 | ASTM B444 |
| 686 | N06686 | ASTM B619 / B622 / B626 |
| 690 | N06690 | ASTM B163 / B167 / B829 |
| 693 | N06693 | ASTM B167 |
| 718 | N07718 | AMS 5589 / 5590 |
Equivalent Grades
Common grades: Inconel 625 (UNS N06625, W.Nr. 2.4856), 718 (UNS N07718, 2.4668, EN NiCr19Fe19NbMo3), 600 (UNS N06600, 2.4851). These match ISO NA21N or JIS NW4400, streamlining sourcing for procurement heads.
Product Forms and Availability
Available as seamless (OD 3-127mm, lengths to 12m), welded (up to 1524mm OD, Sch 10-80), suited for umbilicals and heat exchangers. Inconel hex bar complements for forged fittings in OEM assemblies.
Chemical Composition
Inconel 625: Ni balance (min 58%), Cr 20-23%, Mo 8-10%, Nb 3.15-4.15%, Fe 5% max, C 0.1% max. 718 adds Ti/Al for precipitation hardening; 600 has higher Fe (6-10%). Optimized for weldability and pitting resistance.
Mechanical and Physical Properties
625 yields 414 MPa min, tensile 827 MPa, elongation 30%; density 8.44 g/cm³, melt 1290-1350°C. Thermal conductivity 9.8-17.2 W/m-K, expansion 12.8-17.4 × 10⁻⁶/K. Maintains strength at 650°C.
Applications by Industry
Oil & gas deploys Inconel tubes for downhole and flare systems, resisting sour corrosion better than duplex steels; chemical processing handles oxidizing acids. Marine for propeller shafts; pharma for sterile processing; power for gas turbines.
The nickel alloys market, including Inconel, reached $18B in 2025, with oil & gas at 35% share.
Inconel® vs Common Alternatives
| Property | Inconel 625 | Hastelloy C-276 | SS316 | Incoloy 825 |
|---|---|---|---|---|
| Tensile (MPa) | 827 | 690-827 | 515-690 | 586-690 |
| Yield (MPa) | 414 | 283 | 205 | 241 |
| Max Temp (°C) | 980 | 1040 | 870 | 540 |
| Oxidizing Resistance | Excellent | Good | Fair | Moderate |
Inconel leads in high-temp oxidation and SCC resistance, ideal for aero-derivative power.
Certifications and Compliance
Supplied with EN10204 3.1/3.2 certs, PMI, UT/RT, compliant with NACE MR0175/ISO 15156 for sour service. Mumbai export hubs ensure PED/CE marking, IBR approval for boilers.
FAQ
Global Export Destinations
We ship worldwide from Mumbai. See every destination we export to on our export markets page.
Domestic Supply Network
We deliver across India from our Mumbai stockyard. See every city we supply on our supply locations page.
Inconel® tubes offer engineered reliability for demanding environments, validated by certifications, NACE compliance, and field-proven durability across industries. How will Inconel elevate your next project?