Inconel Hex Bars: High-Performance Nickel Alloys for Extreme Heat and Corrosion
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During a gas turbine overhaul in a power plant, standard stainless steel fasteners oxidized and crept under cyclic high temperatures exceeding 800°C, leading to vibration-induced failures and emergency shutdowns. Switching to Inconel hex bars restored integrity, showcasing their superior oxidation resistance and strength retention.
Specifications and Standards
Inconel hex bars comply with ASTM B446/ASME SB446 (625), B166 (600), UNS N06625/N06600/N07718, DIN 2.4856 (625)/2.4648 (718)/2.4851 (600), EN NiCr22Mo9Nb (625). Available in annealed or age-hardened conditions, sizes 6-150mm A/F, lengths to 7m.
Full traceability via MTRs, UT/PMI testing, ISO 9001 certification support export to stringent markets.
Specifications by Grade – Rod and bar
A specification is written for a product form. The standards below are the ones that cover rod and bar; the plate, bar and tube specifications for these grades are different documents and are listed on their own pages.
| Grade | UNS | Rod and bar specification |
|---|---|---|
| 600 | N06600 | ASTM B166 / AMS 5665 |
| 601 | N06601 | ASTM B166 / AMS 5715 |
| 617 | N06617 | ASTM B166 / AMS 5887 |
| 625 | N06625 | ASTM B446 / AMS 5666 |
| 686 | N06686 | ASTM B574 |
| 690 | N06690 | ASTM B166 / B564 |
| 693 | N06693 | ASTM B166 |
| 718 | N07718 | ASTM B637 / AMS 5662 / 5663 |
| 725 | N07725 | ASTM B805 |
| 751 | N07751 | Mill specification |
| 783 | R30783 | AMS 5940 / ASTM B637 |
| X-750 | N07750 | ASTM B637 / AMS 5667-5671 / 5747 |
Equivalent Grades
Inconel 625: UNS N06625, DIN 2.4856, EN 2.4856, AMS 5666; 600: N06600/2.4851/NA14; 718: N07718/2.4668/AMS 5662.
Product Forms and Availability
Hex bars from 4mm to 100mm A/F, in hot-forged, cold-drawn finishes. Rounds, flats, squares also stocked for OEM needs.
Hastelloy hex bars serve as a strong complement for severe acid environments.
Chemical Composition
Inconel 625: Ni 58% min, Cr 20-23%, Mo 8-10%, Nb+Ta 3.15-4.15%, Fe 5% max, C 0.10% max. Enhances strength via Nb-Mo interaction.
Mechanical and Physical Properties
625: Tensile 820 MPa (annealed), yield 414 MPa, elongation 30-36%, density 8.44 g/cm³, modulus 207 GPa, thermal expansion 12.8 µm/m°C. Retains properties to 980°C.
718 age-hardens to 1275 MPa tensile; 600 offers 550-690 MPa for oxidation.
Applications by Industry
Chemical Processing
Reactor components resist sulfuric/phosphoric acids, pitting; preferred over SS for creep resistance.
Oil & Gas
Offshore flanges, sour gas wellheads endure H2S/chlorides; 80% of subsea fasteners use Ni-Cr alloys.
Marine
Exhaust systems, props resist seawater corrosion at elevated temps.
Pharma
Cleanroom fittings maintain purity under steam/chemicals.
Power Generation
Turbine bolts, heat exchangers handle 700°C+ combustion gases.
OEM, Fabricators, Stores
Weldable/machinable for aerospace/power prototypes.
Inconel vs. Common Alternatives
| Property | Inconel 625 | Hastelloy C276 | Monel 400 | 316 SS |
|---|---|---|---|---|
| Tensile (MPa) | 820 | 690-790 | 480-620 | 515-690 |
| Oxidation Resistance | Excellent to 980°C | Good to 1040°C | Fair to 480°C | Poor |
| Acid Resistance | Good | Excellent | Poor | Moderate |
| Creep Strength | High | Moderate | Low | Low |
Inconel leads in high-temp oxidation/creep; Hastelloy for acids.
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.
Supported by proven standards, comprehensive testing, and exceptional performance under heat and corrosion, Inconel hex bars empower confident decisions for fabricators and procurement leaders. Will Inconel hex bars be your choice for the next high-demand project?