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Inconel 625

metal

nickel superalloy — solid-solution-strengthened

UNS N06625Alloy 625IN625Nicrofer 6020 hMoHaynes 625AMS 5666 (wrought ref.)
Density
8.44 g/cm³
YS (LPBF as-built (XY))
540–680 MPa
UTS (LPBF as-built (XY))
820–980 MPa
Elongation (LPBF as-built (XY))
25.0–48.0 %
Elastic modulus
195–215 GPa
Thermal conductivity
9.8 W/m·K

Composition — UNS N06625 / ASTM F3056-14

ElementMin %Max %Notes
Ni58.00—balance. High Ni for corrosion resistance in reducing acids
Cr20.0023.000Cr₂O₃ scale — oxidation and high-temperature corrosion resistance
Mo8.0010.000Primary solid solution strengthener; pitting and crevice corrosion resistance in seawater
Nb3.154.150Solid solution strengthening; also forms Laves phase and δ (delta) during LPBF thermal cycling
Fe—5.000
Co—1.000
Al—0.400
Ti—0.400
C—0.100
Mn—0.500
Si—0.500
P—0.015
S—0.015
Ta—0.050

Mechanical & thermal properties — 4 conditions

PropertyLPBF as-built (XY)LPBF as-built (Z)LPBF stress-relieved (XY)LPBF solution-annealed (isotropic)
Elastic modulus195–215 GPa———
Yield strength (0.2%)540–680 MPa470–600 MPa520–650 MPa390–490 MPa
Ultimate tensile strength820–980 MPa730–880 MPa790–940 MPa720–850 MPa
Elongation at break25.0–48.0 %20.0–42.0 %28.0–50.0 %40.0–60.0 %
Hardness (HV)250–320 HV10——200–245 HV10
Fatigue strength370–490 MPa———
Density8.44 g/cm³———
Thermal conductivity9.8 W/m·K———
CTE12.6–13.6 µm/m·K———

Values shown as min–max where a spread is reported, otherwise as typical ± unit. Ranges reflect inter-source variation, not single-sample scatter. All values are for AM-processed specimens unless noted.

Engineering considerations

  • Post-processing selection: as-built (highest strength, Laves present) vs stress-relieved (balanced) vs solution-annealed (maximum ductility, corrosion, and isotropic properties). Oil & gas typically uses stress-relieved; subsea structural uses solution-annealed.
  • NACE sour service: ISO 15156-3 (NACE MR0175) qualifies solution-annealed LPBF IN625 for H₂S-containing environments. Verify hardness ≤40 HRC (≈388 HV) — as-built LPBF typically passes.
  • Distortion control: IN625 has even lower thermal conductivity than IN718 — larger parts require simulation-based distortion compensation before build. Mandatory stress-relief before removal from plate.
  • DED cladding: LPBF IN625 is used for near-net-shape parts; DED IN625 is the dominant process for corrosion-resistant overlays on carbon and low-alloy steel (API 6A, NACE HIC-resistant). DED achieves 2–4 mm/h deposition on large surfaces.
  • Anisotropy reduction: solution anneal at 1150°C recrystallises columnar grains and makes properties near-isotropic. Required when design assumes isotropic material (common in pressure vessel codes).
  • Cryogenic service: solution-annealed LPBF IN625 retains excellent ductility and fracture toughness at -196°C — suitable for LNG valves, pump housings, and manifolds.
  • Oxidation protection: IN625 is protected to ~980°C by Cr₂O₃ scale. Above 1000°C, protective scale becomes unstable — use wrought IN625 forging or cast IN713 for higher temperatures.
  • Powder re-use: Mo and Nb are heavy elements that segregate to powder surfaces with thermal cycling. Monitor chemistry carefully — limit re-use to 20–25 cycles without blending to virgin.

Advantages

  • Outstanding corrosion resistance across an extremely wide range of environments: oxidising, reducing, seawater, chloride, acids
  • No complex post-heat-treatment required — as-built or stress-relieved meets most structural and corrosion requirements
  • Good strength and ductility maintained from cryogenic temperatures (-196°C) to ~815°C
  • Pitting resistance equivalent number (PREN) ~52 — far exceeds super-duplex stainless (~43)
  • NACE MR0175 / ISO 15156-3 qualified for sour-service (H₂S-containing) environments
  • Excellent resistance to sensitisation — no age-hardening means no Cr-depletion risk
  • DED/WAAM IN625 is the leading cladding alloy for offshore and chemical industry repair
  • Good weldability with IN625 or IN82 filler wire

Limitations

  • No precipitation hardening — cannot approach IN718 or CoCrMo strength levels (max YS ~700 MPa as-built)
  • Very low thermal conductivity (9.8 W/m·K) — highest residual stress accumulation of LPBF nickel alloys; support and scan strategy critical
  • Laves phase in as-built condition reduces ductility and creep resistance vs. wrought annealed
  • High density (8.44 g/cm³) — heaviest common AM metal after CoCrMo
  • Elevated cost relative to stainless steel — justify with genuine corrosion or temperature requirement
  • LPBF fatigue database is sparse vs. IN718 — conservative design factors needed for cyclic-loaded components
  • δ-phase precipitation between 650–980°C — if stress-relief temperature is too low, δ-phase can reduce ductility
  • Mo-rich Laves phase at grain boundaries reduces sour-service corrosion resistance unless dissolved by solution anneal

Typical applications

Subsea wellhead components and riser clampsHeat exchanger tubing for aggressive chemical environmentsFuel nozzles and combustor liners (aerospace)Exhaust system components for marine gas turbinesChemical reactor vessels and piping (strong acids, halides)Cryogenic LNG vessel hardware and fittingsFlare tips and high-temperature exhaust componentsCorrosion-resistant overlays via DED on carbon steel componentsNuclear waste handling fixturesDeep-sea instrumentation housings

Industries

aerospaceenergyindustrial

Standards & certifications

ASTM-F3056established

IN625 (UNS N06625) parts produced by powder bed fusion — composition, powder, and minimum mechanical property requirements

aerospaceenergyindustrial

YS ≥345 MPa, UTS ≥690 MPa, El ≥25% minimum. Deliberately conservative — LPBF IN625 typically exceeds by 50–100%.

ISO-52904established

Process quality assurance for safety-critical PBF parts

aerospaceenergy
AMS-7000established

LPBF process requirements for aerospace production

aerospacedefence
ASTM-E8established

Tensile test method for acceptance testing

aerospaceenergyindustrial

Compatible AM processes (4)

Laser Powder Bed Fusion20–100 µm layersDirected Energy Deposition — Laser Powder200–1000 µm layers
DED-Wire
Wire Arc Additive Manufacturing1000–10000 µm layers

Other metal materials

Ti-6Al-4V Grade 5titanium alloy — alpha-beta316L Stainless Steelaustenitic stainless steel17-4PH Stainless Steelmartensitic precipitation-hardening stainless steelAlSi10Mgaluminium-silicon alloy (cast grade adapted for AM)AlSi7Mg Aluminium Alloyhypoeutectic Al-Si-Mg precipitation-hardenable aluminium alloyInconel 718nickel superalloy — precipitation-hardenedCoCrMocobalt-chromium alloy (biomedical and aerospace grade)Maraging Steel MS1 (18Ni-300)maraging steel (ultra-high-strength, precipitation-hardened)H13 Tool Steelchromium-molybdenum hot-work tool steel

Related calculators

HT AdvisorStandard stress-relief, solution, and aging cycles for AM metals (Ti-6Al-4V, IN718, 17-4PH, AlSi10Mg, 316L, CuCrZr) per AMS, ASTM F3301, and AMS 5664.DistortionEstimate residual stress and distortion risk index (σ/σ_y) for LPBF and DED builds. Mercelis-Kruth model with preheat sensitivity table.VEDCompute LPBF VED from power, scan speed, hatch, and layer thickness. Includes process windows for common alloys.Melt PoolLPBF / DED melt pool depth, width, and cooling rate from the Rosenthal moving heat source solution. Absorptivity, thermal diffusivity, and solidification velocity.
Last reviewed: 2026-05-04 · v1 · Sources: ASTM-F3056, eos-in625-2023, renishaw-in625-2023, marchese-2017-in625, dinda-2009-in625, debroy-2018-review, yadollahi-2017-fatigue, ASTM-E8, ISO-52904