Inconel X-750, Inconel 625, and Inconel 718 are all nickel-chromium-based superalloys recognized for their remarkable strength, corrosion resistance, and ability to withstand extreme environments. While they share similarities, each alloy has unique properties and applications that make it suitable for specific uses, especially in aerospace, chemical processing, and power generation industries. Below is a detailed comparison of these three superalloys.
Chemical Composition
The chemical composition of each alloy influences its structural properties, corrosion resistance, and performance under high-temperature conditions.
Chemical Composition
| Element | Inconel X-750 | Inconel 625 | Inconel 718 |
|---|---|---|---|
| Nickel (Ni) | 70% min | 58-63% | 50-55% |
| Chromium (Cr) | 14-17% | 20-23% | 17-21% |
| Iron (Fe) | Balance | Balance | Balance |
| Molybdenum (Mo) | 2.5-3.0% | 8-10% | 2.8-3.3% |
| Niobium (Nb) | 0.5-1.0% | 3.0-4.0% | 4.75-5.5% |
| Titanium (Ti) | None | 0.4-0.7% | 0.65-1.15% |
| Carbon (C) | ≤0.05% | ≤0.10% | ≤0.08% |
Mechanical Properties
The mechanical properties vary significantly among these alloys, impacting their performance in various applications.
Mechanical Properties
| Property | Inconel X-750 | Inconel 625 | Inconel 718 |
|---|---|---|---|
| Yield Strength (MPa) | 600 – 1,100 | 380 – 830 | 970 – 1,380 |
| Ultimate Tensile Strength (MPa) | 700 – 1,100 | 700 – 1,200 | 1,270 – 1,380 |
| Elongation (%) | 30% (min) | 30% (min) | 15% (min) |
| Hardness (Rockwell B) | 35-42 | 40-50 | 40-44 |
High-Temperature Performance
All three alloys are designed to perform well at high temperatures, but with varying limits and properties.
High-Temperature Performance
| Feature | Inconel X-750 | Inconel 625 | Inconel 718 |
|---|---|---|---|
| Service Temperature | Up to 1,400°F (760°C) | Up to 1,800°F (982°C) | Up to 1,300°F (700°C) |
| Oxidation Resistance | Excellent | Excellent | Good |
| Creep Resistance | Excellent with additional stability | Very good | Very good |
Corrosion Resistance
Corrosion resistance is critical for all three alloys, especially in acidic or high-salinity environments.
Corrosion Resistance
| Corrosion Type | Inconel X-750 | Inconel 625 | Inconel 718 |
|---|---|---|---|
| General Corrosion | Excellent | Excellent | Very good |
| Pitting Corrosion | Excellent | Excellent | Very good |
| Stress Corrosion Cracking | Good | Excellent | Moderate |
| Acid Resistance | Very good | Excellent | Good (in moderate concentrations) |
Weldability
Weldability is an essential consideration for these alloys, particularly in construction and manufacturing.
Weldability Comparison
| Feature | Inconel X-750 | Inconel 625 | Inconel 718 |
|---|---|---|---|
| General Weldability | Good; usually does not require preheating | Good; may require preheating | Good, but requires preheating |
| Post-Weld Heat Treatment | Not usually required | Generally not required | Required to relieve stresses |
| Filler Material | ERNiCr-3 | ERNi625 | ERNiFeCr-3 |
Applications
| Application Area | Inconel X-750 | Inconel 625 | Inconel 718 |
|---|---|---|---|
| Aerospace Industry | Gas turbines, combustion chambers | Aerospace components under high thermal stress | Turbine engines, structural components |
| Chemical Processing | Heat exchangers, aerospace valves | Chemical processing equipment | High-temperature reactors |
| Oil and Gas | Downhole tubing and valves | Components for oil and gas extraction | Oil and gas processing equipment |
| Power Generation | Boiler tubes, components | Turbines and heat exchangers | Gas and steam turbine components |
| Marine Applications | Components in aggressive environments | Marine applications due to excellent corrosion resistance | Less common but used when required |
Summary of Differences
| Feature | Inconel X-750 | Inconel 625 | Inconel 718 |
|---|---|---|---|
| Nickel Content | 70% min | 58-63% | 50-55% |
| Chromium Content | 14-17% | 20-23% | 17-21% |
| Molybdenum Content | 2.5-3.0% | 8-10% | 2.8-3.3% |
| Temperature Resistance | Up to 1,400°F (760°C) | Up to 1,800°F (982°C) | Up to 1,300°F (700°C) |
| Applications | Versatile in oil, gas, and aerospace | Excellent for marine and chemical applications | Preferred in aerospace and high-stress scenarios |
Conclusion
Inconel X-750, Inconel 625, and Inconel 718 each offer unique properties that cater to different applications.
Inconel X-750 is well-suited for high-temperature and high-stress environments, particularly in power generation and oil and gas applications.
Inconel 625 provides excellent corrosion resistance and high-temperature strength, making it ideal for marine and chemical processing applications.
Inconel 718 is characterized by its exceptional mechanical properties and is favored in aerospace applications for turbine components and structures.
Our product range
| Product Form | Standard Specifications & Dimensions | Common Alloys (Examples) | Typical Standards |
|---|---|---|---|
| Bar & Rod | Round Bar: Diameter: 3mm ~ 300mm Hexagon Bar: Across Flats: 5mm ~ 100mm Square Bar: Width: 5mm ~ 150mm Length: Random, Cut-to-length, or Coils (small diameters) |
Alloy 200/201 Monel 400/K-500 Inconel 600/601/625/718 Incoloy 800/800H/825 Hastelloy C-276/C-22/B-2/B-3 |
ASTM B160, B164, B166 EN/DIN 2.4066, 2.4816, 2.4851 ASME SB-166, SB-167 |
| Wire | Diameter: 0.1mm ~ 12mm Form: Coils, spools, or straight lengths Finish: Bright, pickled, annealed |
Alloy 200/201 Inconel 600/625/X-750 Incoloy 825 |
ASTM B166, B167 EN/DIN 17752 |
| Sheet & Plate | Thickness (Sheet): 0.1mm ~ 5.0mm Thickness (Plate): 5.0mm ~ 100mm+ Width: Up to 2000mm (depending on alloy/thickness) Length: Up to 6000mm or as required |
Alloy 200/201 Monel 400 Inconel 600/625/718 Incoloy 800H/825 Hastelloy C-276 |
ASTM B162, B168, B409 EN/DIN 17742, 17744 |
| Strip & Foil | Thickness (Strip): 0.05mm ~ 2.0mm Thickness (Foil): 0.02mm ~ 0.05mm Width: Up to 600mm Condition: Cold rolled, annealed, tempered |
Alloy 200/201 Inconel 600/625 Incoloy 825 |
ASTM B162, B168 |
| Pipe & Tube | Seamless Pipe (ASTM B161/B167): - OD: 3/16" ~ 14" (6mm ~ 355mm) - Schedule: SCH 5S to XXS Welded Tube (ASTM B163/B516): - OD: 6mm ~ 300mm - Wall Thickness: 0.5mm ~ 10mm |
Alloy 200/201 Monel 400 Inconel 600/625 Incoloy 800H/825 Hastelloy C-276 |
ASTM B161, B163, B167, B516 ASME SB-163, SB-167 |
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Our factory and testing
Our core factory and collaborative production system are equipped with modern precision cutting, processing, and heat treatment equipment, focusing on transforming raw materials into semi-finished and finished products that meet stringent standards. To ensure that every batch of materials meets or exceeds specifications, we have established a comprehensive end-to-end quality inspection system. From material properties analysis (PMI) upon raw material warehousing to dimensional accuracy control during production, and finally to mechanical property testing (such as tensile strength and hardness) and non-destructive testing before final shipment, every step is rigorously controlled by our professional quality inspection team. We promise to provide an authoritative, online-verifiable original manufacturer's material certificate (MTC 3.1) for every order, and can arrange for third-party certification bodies (such as SGS, BV, and TUV) to conduct on-site inspections and issue certificates upon customer request.
