Inconel 718 and Inconel 625 are nickel-based alloys with excellent comprehensive properties, and both belong to the inconel alloy series. They have good high temperature resistance and corrosion resistance. The difference is that the performance of Inconel 718 is more inclined to high strength. Inconel 625 more prone to corrosion resistance.
The following is a comparison of these 2 alloys from several aspects, so that you can have a more comprehensive and clear understanding of the alloy.
Inconel 718 and Inconel 625
Inconel 718 (UNS N07718, W.Nr. 2.4668) is a high strength, corrosion resistant nickel-chromium alloy for use in temperatures from -423°F to 1300°F. The yield strength below 650 ℃ ranks first in the deformed superalloy, and has good fatigue resistance, radiation resistance, oxidation resistance, corrosion resistance, as well as good processing performance and good welding performance. It can manufacture various parts with complex shapes, and has been widely used in the above temperature range in aerospace, nuclear energy, petroleum industry and extrusion dies. The alloy is a precipitation-strengthened alloy with a density of 8.19g/cm³.
Inconel 625 (UNS N06625 , W.Nr. 2.4856) is a solid solution strengthened nickel base wrought superalloy with excellent corrosion resistance and high oxidation properties, good tensile and fatigue properties from low temperature to 1800°F , and resistant to stress corrosion in a salt spray atmosphere. Therefore, it can be widely used in the manufacture of aero-engine parts, aerospace structural parts and chemical equipment, with a density of 8.44 g/cm³.
Comparison of element content
|
Chemical Composition |
|||||||||||||||
|
Element |
C |
Cr |
Nb+Ta |
Mo |
Co |
Mn |
Ti |
P |
Fe |
Ni |
B |
Al |
Si |
S |
Cu |
|
Inconel 718 |
0.08Max |
17.0-21.0 |
4.75-5.50 |
2.8-3.3 |
1.0Max |
0.35Max |
0.65-1.15 |
0.015Max |
11.1-22.5 |
50-55 |
0.006Max |
0.2-0.8 |
0.35Max |
0.015Max |
0.3Max |
|
Inconel 625 |
0.1Max |
20.0-23.0 |
3.15-4.15 |
8.0-10.0 |
1.0Max |
0.5Max |
0.4Max |
0.015Max |
5.0Max |
58Min |
0.4Max |
0.5Max |
0.015Max |
||
Si element can improve the corrosion resistance and hardness of the alloy. Adding appropriate Si element to the nickel alloy can promote the formation of a dense silicon oxide protective film in the corrosive medium and improve the corrosion resistance of the material. The silicon ratio of Inconel 625 is higher than that of Inconel. The content of 718 is high, so inconel 625 has better corrosion resistance.
Inconel 718 has a much higher iron content than Inconel 625, and its content of nickel, chromium, and molybdenum is relatively small. Nickel and chromium can improve the corrosion resistance of the alloy, and molybdenum can supplement the reduction resistance of the alloy. Therefore, the corrosion resistance of Inconel 625 is much greater than that of Inconel 718.
Inconel 718 has a higher niobium content than Inconel 625, thus allowing age hardening, allowing annealing and welding without spontaneous hardening during heating and cooling. Inconel 625 does not have this feature.
Mechanical properties
| Mechanical Properties of Alloy 718 and Alloy 625 | ||
| Inconel 718 | Inconel 625 | |
| Tensile strength(MPa) | 1275 | 690 |
| Yield Strength(MPa) | 1034 | 276 |
Heat treatment method
Inconel 718 is a precipitation-strengthened alloy, so it is generally subjected to aging treatment after solution treatment. The purpose is to fully analyze the precipitation strengthening phase and improve the strength of the alloy. There are two heat treatment methods for this alloy:
a. Solution annealing at 1700-1850°F, rapid cooling in water, then precipitation hardening at 1325°F for 8 hours, furnace cooling to 1150°F, holding at 1150°F for a total aging time of 18 hours, Next, air cooling is performed.
b. Solution annealed at 1900-1950°F, then rapidly cooled in water, precipitation hardened at 1400°F for 10 hours, furnace cooled to 1200°F, held at 1200°F for 20 hours total aging time, final Air cooling.
The properties of the alloys obtained by the two heat treatment methods are different and can be selected according to the actual application. The first heat treatment method is performed by default
The standard heat treatment method for 625 alloy is solution treatment, and the 625 alloy after solution treatment can achieve the best performance state.
Industry application
Inconel 718 and Inconel 625 can be widely used in aerospace, marine engineering, oil and gas, electric power and other industries. In addition, INconel 718 is also widely used in the automobile manufacturing industry. Due to its high corrosion resistance, Inconel 625 can also be used in pollution treatment, chemical processing and other fields.
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.
