Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Incoloy 800H vs Inconel 617 — High-Temp Creep + Oxidation
Incoloy 800H (UNS N08810) and Inconel 617 (UNS N06617) compete for petrochemical and gas-turbine service above 800°C. 800H is the cost-effective Fe-Ni-Cr workhorse for ASME pressure vessels and reformer pigtails up to ~982°C; Inconel 617 is the Ni-Cr-Co-Mo solid-solution premium for service above 950°C where its Co + Mo combat creep-rupture better than 800H. Selection depends on operating temperature window, cost ratio (617 is roughly 1.8 to 2.5 times the cost of 800H raw stock), and whether the service includes thermal cycling.
Need a quote on either alloy? Request RFQ or call +91-22-66157017. Material certs EN 10204 3.1 / 3.2 supplied.
Chemistry — UNS N08810 vs UNS N06617
Incoloy 800H (UNS N08810, Werkstoff 1.4876, X10NiCrAlTi32-21) is an iron-base Fe-Ni-Cr alloy with controlled carbon 0.05 to 0.10 percent and ASTM grain size 5 or coarser. Inconel 617 (UNS N06617, Werkstoff 2.4663a) is a nickel-base Ni-Cr-Co-Mo solid-solution alloy with cobalt 10 to 15 percent and molybdenum 8 to 10 percent acting as the primary strengtheners. The Fe / Ni ratio flip is what changes the entire creep-rupture envelope.
| Element | Incoloy 800H (N08810) | Inconel 617 (N06617) |
|---|---|---|
| Ni | 30.0 to 35.0 | 44.5 min |
| Fe | 39.5 min (remainder) | 3.0 max |
| Cr | 19.0 to 23.0 | 20.0 to 24.0 |
| Co | not specified | 10.0 to 15.0 |
| Mo | not specified | 8.0 to 10.0 |
| Al | 0.15 to 0.60 | 0.8 to 1.5 |
| Ti | 0.15 to 0.60 | 0.6 max |
| C | 0.05 to 0.10 | 0.05 to 0.15 |
See full Incoloy 800H chemical composition and the UNS N08810 specification page for tolerances.
Mechanical Properties — Room Temperature + Creep-Rupture
| Property | Incoloy 800H | Inconel 617 |
|---|---|---|
| Tensile strength (RT, min) | 65 ksi / 450 MPa | 105 ksi / 725 MPa |
| 0.2 percent yield (RT, min) | 25 ksi / 170 MPa | 50 ksi / 345 MPa |
| Elongation (RT, min) | 30 percent | 40 percent |
| 100,000 hr creep-rupture at 800°C | ~38 MPa | ~80 MPa |
| 100,000 hr creep-rupture at 900°C | ~16 MPa | ~40 MPa |
| 100,000 hr creep-rupture at 1000°C | ~6 MPa | ~18 MPa |
| Max sustained service temp | 982°C / 1800°F | 1100°C / 2010°F |
Inconel 617 carries roughly double the creep-rupture strength of Incoloy 800H at every temperature point above 800°C. That premium is the principal reason 617 commands its price. For full data on 800H see the mechanical properties page.
Cost Ratio — Mill Stock Pricing
| Form | Incoloy 800H (baseline 1.0x) | Inconel 617 |
|---|---|---|
| Round bar | 1.0x | 1.8 to 2.2x |
| Seamless pipe / tube | 1.0x | 2.0 to 2.5x |
| Plate / sheet | 1.0x | 1.9 to 2.3x |
| Forgings | 1.0x | 2.2 to 2.5x |
The cobalt content (10 to 15 percent) is the dominant cost driver in 617. Cobalt is an LME-quoted strategic metal with significantly higher price volatility than nickel. Lead time is broadly similar, 8 to 14 weeks mill-direct for either alloy in non-stock sizes.
Application Matrix by Temperature Window
| Service Temperature | Preferred Alloy | Reason |
|---|---|---|
| Up to 815°C / 1500°F | Incoloy 800H | ASME Section VIII qualified, lower cost, adequate creep margin |
| 815 to 900°C | Incoloy 800H or 800HT | 800HT (N08811) extends 800H envelope; cheaper than 617 |
| 900 to 950°C | Evaluate both | Cost / life trade-off depends on cycling severity and inspection budget |
| 950 to 1050°C | Inconel 617 | 800H creep-rupture insufficient; Co+Mo solid-solution wins |
| Above 1050°C | Inconel 617 | Only 617 retains useful creep strength up to 1100°C ceiling |
Typical 800H wins: reformer pigtails, fired-heater tubes, ASME Section VIII pressure vessels, ethylene-cracker convection coils. Typical 617 wins: gas-turbine combustor liners, transition ducts, IGCC syngas coolers, advanced ultra-supercritical (AUSC) boiler superheaters above 700°C steam.
Decision Tree
Step through the following decisions in order:
- Operating temperature ceiling? Below 815°C, default to Incoloy 800H. Above 950°C, default to Inconel 617.
- Service envelope between 815 and 950°C? Calculate creep-rupture margin for the design life. If 800H gives less than 1.5x margin, step up.
- Thermal cycling severity? 617 has better low-cycle fatigue at high temperature; specify 617 for combustor or transition-duct service with >2000 cycles design life.
- Corrosive process stream? Above NACE MR0175 sour-service limits, 617 is preferred. For plain oxidation in clean air, 800H is enough.
- Budget constrained? 800HT (N08811) extends the 800H envelope at ~5 to 10 percent premium over 800H rather than the 80 to 150 percent premium of 617. See the 800 vs 800H vs 800HT page.
Applicable Standards
- Incoloy 800H: ASTM B407 (seamless pipe), B408 (rod), B409 (plate, sheet, strip), B514 (welded pipe), B515 (welded tube), B564 (forgings), ASME SB-407 through SB-564, ASME Code Case 1325, DIN 17460 Werkstoff 1.4876.
- Inconel 617: ASTM B166 (rod, bar, wire), B167 (seamless pipe and tube), B168 (plate, sheet, strip), B564 (forgings), ASME SB-166 through SB-564, ASME Code Case 1956 (high-temperature design data), VdTUEV Werkstoffblatt 485.
- Common to both: EN 10204 3.1 or 3.2 inspection certification, ASME Section IX welder qualification, NACE MR0175 / ISO 15156 sour-service screening.
FAQs
When is Inconel 617 worth the price premium over Incoloy 800H?
When operating temperature consistently exceeds 950°C, when the service involves >2000 thermal cycles over design life, or when the process stream sits above NACE MR0175 sour-service limits. Below 815°C in plain oxidation service, 800H gives essentially equivalent life at less than half the mill cost; the 617 premium goes to waste.
Can Incoloy 800H replace Inconel 617 below 900°C?
Generally yes, provided the design life and creep-rupture margin verify on the lower 800H allowables. ASME Section VIII allowables for 800H are tabulated up to 815°C; for 815 to 982°C the application falls under Code Case 1325. Inconel 617 is qualified to 1100°C. Run the calculation on the lower-bound 100,000-hr rupture stress at the design temperature; if 800H stress + safety factor passes, 800H is the cost-effective answer.
Which welding consumable should I use — ERNiCrCoMo-1 or ERNiCr-3?
ERNiCrCoMo-1 (AWS A5.14, matching Inconel 617 filler) for 617-to-617 welds and for 617-to-800H dissimilar joints where the joint sees 617-side service conditions. ERNiCr-3 (Inconel 82 / 182 filler) is the standard for 800H-to-800H welds. Match the filler to the higher-alloy side of any dissimilar weld so the weld bead survives the worst service condition the joint will see.
What is the heat treatment difference between 800H and 617?
Incoloy 800H is solution-annealed at 1149 to 1177°C followed by rapid air or water cool to dissolve carbides and restore the coarse ASTM-5-or-coarser grain structure that drives its creep performance. Inconel 617 is solution-annealed at 1163 to 1191°C with rapid quench, then optionally aged 200 hours at 730°C for service stability. 800H requires no aging treatment. Specify the heat treatment condition explicitly on the purchase order to avoid mismatch.
Related
- Incoloy 800 vs 800H vs 800HT
- Incoloy 800H vs Inconel 625
- Incoloy 800H vs Inconel 600
- Incoloy 800H vs Inconel family
- UNS N08810 specification
Ready to specify? TorqBolt QA-QC will quote either alloy with full mill certification (EN 10204 3.1 / 3.2), NACE compliance review, and lead-time confirmation. Send your spec or WhatsApp +91 22 66157017.
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