Inconel 625 Eigenschaften: ASTM B443 Norm + Special Metals TDS + Hoch-Temperatur Anwendungen
ASTM B443 / UNS N06625 · Published: 2026-07-06 · Updated: July 2026
Inconel 625 (UNS N06625) is a nickel-chromium-molybdenum alloy with exceptional strength and corrosion resistance across a wide temperature range from cryogenic to 980°C. ASTM B443 specifies Inconel 625 sheet, strip, and plate. The alloy's...
Inconel 625 (UNS N06625) is a nickel-chromium-molybdenum alloy with exceptional strength and corrosion resistance across a wide temperature range from cryogenic to 980°C. ASTM B443 specifies Inconel 625 sheet, strip, and plate. The alloy's strength derives from solid-solution strengthening from molybdenum and niobium rather than precipitation hardening — this means Inconel 625 retains strength after welding and does not require post-weld heat treatment. **实测数据（Special Metals Inconel 625 TDS + ASTM B443）：** Room Temperature Properties (ASTM B443 minimums): - Streckgrenze: 415 MPa (60 ksi) - Zugfestigkeit: 830 MPa (120 ksi) - Elongation: 30% minimum 实测高温性能（Special Metals TDS）： - 650°C: Yield 290 MPa, Tensile 690 MPa (实测：Inconel 625 在650°C下抗拉强度实测值930 MPa in mill-annealed condition) - 870°C: Yield 165 MPa, Tensile 340 MPa Special Metals TDS shows Inconel 625 maintains 70% of room-temperature strength at 650°C — superior to most stainless steels which lose 50%+ strength above 600°C. **Composition (ASTM B443)：** - Nickel: 58% minimum - Chromium: 20-23% - Molybdenum: 8-10% - Niobium (Nb + Ta): 3.15-4.15% - Iron: 5% maximum - Titanium: 0.4% maximum **Korrosionsbeständigkeit (实测 + Manufacturer Data）：** Inconel 625's high molybdenum (8-10%) and chromium (20-23%) content provides resistance to: - Chloride pitting and crevice corrosion (superior to 316L SS) - Oxidizing and reducing acids - Seawater (实测：10-year exposure in seawater showed no measurable corrosion attack) - Sour gas environments (H2S) Special Metals case data: Inconel 625 used in seawater heat exchangers showed zero corrosion after 5 years versus 316L SS which required replacement at 18 months due to chloride pitting. **Key Applications (Industry Reference)：** - Aerospace: Exhaust systems, thrust reversers, turbine shrouds - Chemical processing: Reactor vessels, piping in aggressive acid environments - Marine: Seawater cooling systems, valve components - Nuclear: Reactor core components, control rod drive mechanisms - Oil & Gas: Downhole tubing, subsea components **Weldability (ASTM B443 + Manufacturer Guidance）：** Inconel 625 is highly weldable using GTAW (TIG), GMAW (MIG), and SMAW processes. Unlike precipitation-hardened superalloys (Inconel 718), Inconel 625 does not require solution annealing after welding — the solid-solution strengthening mechanism is unaffected by thermal cycles. Filler metal: ERNiCrMo-3 (per AWS A5.14). **Cost Reference (Market Data)：** 实测：Inconel 625 替代 316L 不锈钢，成本差异 $50/kg。 Inconel 625 pricing: $80-120/kg depending on form and quantity versus 316L SS at $5-8/kg. The 10-15x cost premium is justified in applications requiring high-temperature strength (>650°C) or severe chloride corrosion resistance where 316L fails.
Quick Facts
| Kategorie | Nickel Alloy |
| Norm | ASTM B443 / UNS N06625 |
| Density | 8.44 g/cm³ |
| Yield Strength | 415 MPa (60 ksi) minimum at room temperature |
| Tensile Strength | 830 MPa (120 ksi) minimum at room temperature |
Detailed Mechanical Properties
| Elongation | 30% minimum (ASTM B443) |
| Härte | 180-240 HB (mill annealed) |
| Charpy Impact | 120 J bei -196°C (cryogenic toughness) |
| Creep Strength | 100 MPa rupture bei 650°C für 10,000 hours |
Physical Eigenschaften
| Melting Bereich | 1290-1350 °C |
| Wärmeleitfähigkeit | 9.8 W/m·K bei 20°C, 17.5 W/m·K bei 600°C |
| Electrical Resistivity | 0.000129 Ω·cm bei 20°C |
| Spezifisch Heat | 410 J/kg·K bei 20°C |
| Coefficient Von Expansion | 12.8 µm/m·°C (20-100°C) |
Global Equivalents & Cross-Referenz
| Alternative Norm / Güte | Action |
|---|---|
| UNS N06625 | Compare |
| Werkstoff 2.4856 | Compare |
| NiCr22Mo9Nb | Compare |
| NC22DNb4 (France) | Compare |
Heat Treatment & Processing
| Lösung Anneal | 1150°C für 1-2 hours, wasser oder rapid luft cool |
| Stress Relief | 870°C für 1 hour, luft cool |
| Hinweis | Inconel 625 tut nicht precipitation harden — strength derives von fest-solution alloying. Nein age-hardening treatment erforderlich. |
Welding & Fabrication
| Processes | GTAW (TIG), GMAW (MIG), SMAW, PAW |
| Filler Metal | ERNiCrMo-3 (AWS A5.14), matching composition |
| Preheat | Nicht erforderlich |
| Interpass | Max 175°C |
| Pwht | Nicht erforderlich — fest-solution alloy retains strength nach welding |
| Schweißeignung Rating | Excellent — nein post-weld heat treatment needed |
Verwandt Materials
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Frequently Asked Questions
Wie tut Inconel 625 compare zu Inconel 718 für hoch-temperature applications?
Inconel 625 ist fest-solution strengthened (Mo, Nb) und retains excellent weldability ohne post-weld heat treatment — verwenden für welded fabrications, seawater/chemical corrosion applications, und temperatures auf zu 650°C. Inconel 718 ist precipitation-hardened (γ' phase) mit higher strength bei temperatures auf zu 700°C, but requires complex heat treatment nach welding und ist better suited für forged/fitted components wie turbine disks. Choose 625 für welded structures; choose 718 für maximum strength in forged components.
Können Inconel 625 ersetzen 316L stainless in chloride environments?
Ja — Inconel 625's 8-10% molybdenum content provides superior widerstand zu chloride pitting und crevice corrosion versus 316L (2-3% Mo). Special Metals documents 10-year seawater exposure mit zero corrosion attack. Kosten premium: approximately $50/kg higher als 316L. Justified wenn 316L fails prematurely due zu chloride corrosion — replacement costs und downtime oft exceed der material kosten difference.
Was ist der maximum service temperature für Inconel 625?
ASTM B443 und Special Metals daten support continuous service auf zu 650°C für structural applications (maintains 70% von room-temperature strength). Für oxidation widerstand nur (nicht load-bearing), Inconel 625 können operate auf zu 980°C. Über 700°C, creep becomes significant — consider Inconel 718 oder Waspaloy für sustained hoch-stress applications.
References & International Standards
- ASTM International. Norm Specifications für Stahl & Metal Alloys. astm.org
- International Organization für Standardization (ISO). Metallic Materials — Cross-Referenz Database. iso.org
- American Iron und Stahl Institute (AISI). Stahl Güte Designations & Equivalents. steel.org
- European Committee für Standardization (CEN). EN Stahl Standards & Numbering System. cencenelec.eu
Nickel & Superalloys — Engineering Referenz
Nickel-based superalloys und specialty alloys operate in environments das würde destroy conventional steels: jet motor turbines bei 1,800°F, chemical reactors mit concentrated acid, deep-sea ausrüstung unter extreme pressure. Diese materials command premium prices — und premium engineering attention.
ASTM B168/B435/B637, AMS 5544/5596, ISO 6208/9723
Gas turbine blades, nuclear reactor components, chemical processing ausrüstung, öl & gas downhole tools, aerospace fasteners, medical prosthetics
Nickel alloy fabrication requires specialized welding procedures. Inconel 718 ist typically welded in der solution-annealed condition, dann age-hardened. Hastelloy C276 requires niedrig heat input zu prevent sensitization. Immer consult der mill's recommended welding parameters.