Introduction: Inconel alloys 600 and 625 are solid solution strengthened Inconel alloys. Because of their different chemical compositions, they have different corrosion resistance and strength. This article will compare these two alloys from all aspects to help you make the right choice for your project.
1. Basic information
1. Inconel 600
Name: Inconel 600
W.Nr. 2.4816
Brand: INCONEL®
Substrate: nickel, chromium, iron
Type: solid solution strengthened alloy
Density: 8.47 g/cm³
Operating temperature: high temperature
2. Inconel 625
Name: Inconel 625
UNS N06625
W.Nr. 2.4856
Brand: INCONEL®
Substrate: nickel, chromium, molybdenum, niobium
Type: solid solution strengthened alloy
Density: 8.44 g/cm³
Operating temperature: high temperature
2. Introduction
1. Inconel 600
INCONEL® (Nickel-Chromium-Iron) Alloy 600 (UNS N06600/W.Nr. 2.4816) is a standard engineering material used in applications requiring corrosion and heat resistance. The alloy also has excellent mechanical properties, presenting an ideal combination of high strength and good processability.
2. Inconel 625
INCONEL® Nickel-Chromium Alloy 625 (UNS N06625 / W.Nr. 2.4856) is widely used due to its high strength, excellent formability (including joining) and excellent corrosion resistance. Service temperature range is from cryogenic to 1800°F (982°C).
3. Chemical composition
It can be seen from the comparison of chemical composition that Alloy 625 has stricter control over the content of impurity elements (phosphorus and manganese) than Alloy 600. Therefore, the higher purity of Alloy 625 also results in superior properties.
1. Phosphorus
Phosphorus plays a dual role in superalloys. There is no specified range for phosphorus content in Alloy 600. If the phosphorus content is too high, it will cause the precipitation of harmful phases, thus affecting the properties of the alloy. In Alloy 625, the phosphorus content is carefully designed. Because a small amount of phosphorus can improve the creep properties of superalloys, this effect reaches its peak at a phosphorus content of 0.016%. Therefore, Inconel 625 alloy uses this principle to achieve better creep strength.
2. Manganese
Manganese in high-temperature alloys can reduce creep properties, and Alloy 625 has more tightly controlled manganese content than Alloy 600. This makes 625 alloy further have better creep strength.
4. Corrosion resistance
1. Inconel 600
2. Inconel 625 is better
Nickel itself has good corrosion resistance in nickel-based alloys, so Inconel 600 and Inconel 625 are both very excellent corrosion-resistant alloys.
1. Chromium
Alloy 625 has a higher chromium content than Alloy 600. Chromium content is the main element responsible for the oxidation resistance of alloys. Therefore, Inconel 625 has better antioxidant capacity than Inconel 600.
2. Molybdenum
Alloy 600 does not contain molybdenum, while Alloy 625 contains more than 8% molybdenum, making Alloy 625 somewhat reducible. This is not available in Alloy 600.
Therefore, Inconel 625 clearly has better overall corrosion resistance in comparison.
5. Mechanical behavior
1. Inconel 600 is better
2. Inconel 625Excellent
1. Molybdenum
Because molybdenum has a large atomic radius, it is an ideal solid solution strengthening element. As mentioned earlier, the molybdenum content gives Alloy 625 its resistance to reduction. At the same time, after solid solution, the molybdenum content also significantly increases the strength of Alloy 625.
2. Niobium and Tantalum
Like molybdenum, niobium and tantalum have very large atomic radii. Therefore, as solid solution strengthening elements, they also improve the mechanical properties of Alloy 625. At the same time, during the heat treatment process, some niobium and tantalum will also form a γ” precipitation strengthening phase, which further enhances the strength of 625.
3. Aluminum and titanium
Although Inconel 625 alloy is a solid solution strengthened alloy (in the original design, aluminum and titanium were only used for refinement), some γ’ precipitation strengthening phases will still precipitate in it. thereby further improving performance.
4. Chromium
When the chromium content is in the range of 20% to 25%, short-range orderly strengthening will occur. The chromium content of alloy 625 is designed to be within this range. thus increasing strength.
5. Cobalt
In nickel-based superalloys, cobalt can reduce the stacking fault energy of the alloy. This also increases the strength of the alloy.
6. Physical properties
Comparison of physical properties of Alloy 600 and Alloy 625:
Inconel 600 Inconel 625
Density, g/cm³ 8.47 8.44
Density, lb/in.³ 0.306 0.305
Melting range, °F 2470-2575 2350-2460
Melting range, °C 1354-1413 1290-1350
Magnetic permeability at 200 Oersted (15.9 kA/m) 1.010 1.0006
Curie temperature, °F -192 <-320
Curie temperature, °C -124 -196
7. Application fields
1. Inconel 600
Automotive, chemical processing, electrical resistance, petroleum processing, heat treatment, welding products
2. Inconel 625
Aerospace, Chemical Processing, Marine, Oil & Gas, Petroleum Processing, Pollution & Waste, Power Generation, Welding Products
Due to its higher strength and better corrosion resistance, Inconel 625 has a wider range of applications than Inconel 600 alloy.
8. Supported products
1. Inconel 600
Seamless tubes and tubes, welded tubes and tubes, capillary tubes, coiled tubes, thick wall tubes, elbows, flanges, reducers, tees, caps, round bars and bars, flat plates, square bars, hexagonal bars, plates , coil, strip, wire, wire, filler metal, welding electrode
2. Inconel 625
Seamless tubes and tubes, welded tubes and tubes, capillary tubes, coiled tubes, thick wall tubes, elbows, flanges, reducers, tees, caps, round bars and bars, flat plates, square bars, hexagonal bars, plates , coil, strip, wire, wire, filler metal, welding electrode
9. Main standards
1. Inconel 600
Condenser and Heat Exchanger Tubes: ASTM B163
Seamless pipe and tube: ASTM B167, ASTM B829
Welded pipe: ASTM B517, ASTM B775
Welded pipe: ASTM B516, ASTM B751
Welding accessories: ASTM B366
Rods, Rods, and Wire: ASTM B166
Forgings: ASTM B564
Plate, sheet and tape: ASTM B168, ASTM B906
2. Inconel 625
Seamless pipe and tube: ASTM B444, ASTM B829
Welded pipe: ASTM B705, ASTM B775
Welded pipe: ASTM B704, ASTM B751
Welding accessories: ASTM B366
Rods and Rods: ASTM B446
Forgings: ASTM B564
Plate, sheet, and tape: ASTM B443
10. Price
1. Inconel 600 low
2. Inconel 625 high
Alloy 625 has a higher degree of alloying (more complex composition), is more difficult to machine, and has better properties, so its price is much higher than Inconel 600.
If Alloy 600 can fully meet your project requirements, we recommend Inconel 600 alloy as your first choice to save costs.
11. Conclusion
Inconel 625 alloy has better overall corrosion resistance than Inconel 600 due to its higher chromium and molybdenum content.
Due to the joint action of various strengthening elements, the mechanical properties of Alloy 625 are better than Alloy 600.
Better properties and more complex composition result in a higher price, so if possible, give preference to the less expensive Alloy 600.
Tianjin Anton Metal Manufacture Co., Ltd. is a company specializing in the production of various nickel-based alloys, Hastelloy alloys and high-temperature alloy materials. The company was established in 1989 with a registered capital of 10.0 million, specializing in the production and sales of alloy materials. Anton Metal’s products are widely used in aerospace, chemical industry, electric power, automobile, nuclear energy and other fields, and can also provide customized alloy material solutions according to customer needs. If you need to know the price consultation of alloy materials or provide customized alloy material solutions, please feel free to contact the sales staff.
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Post time: Dec-14-2023
