Incoloy 825 seamless steel pipe vs Alloy 625: Which performs better in acidic media?
In highly corrosive environments such as reducing acids (sulfuric acid or phosphoric acid) and chloride-containing media, Inconel 625 alloy tubing generally outperforms Incoloy 825 alloy tubing; however, under moderately corrosive conditions, Incoloy 825 tubing offers better resistance to organic acids and is more cost-effective. The higher copper content of Incoloy 825 alloy tubing makes it more suitable for sulfuric acid environments, while the molybdenum and niobium content in Inconel 625 alloy tubing imparts excellent high-temperature strength and resistance to pitting and crevice corrosion. Therefore, the "better" alloy depends on the specific acidic conditions; Inconel 625 alloy tubing is better suited for extremely corrosive environments, while Incoloy 825 seamless alloy tubing is better suited for less corrosive environments.
Will Inconel 625 oxidize?
Inconel 625 alloy (UNS number N06625) is a nickel-based superalloy with high strength and high-temperature resistance. It also exhibits excellent corrosion and oxidation resistance.
Which material is more resistant to acidic media: Incoloy 825 seamless tubing or Alloy 625?
Inco Nickel 625
More resistant to corrosion: Reducing acids such as sulfuric acid and phosphoric acid, as well as high chloride and halide environments.
Reason: Higher molybdenum and niobium content improves resistance to pitting and crevice corrosion, especially at high temperatures.
Advantages: Higher strength, better corrosion resistance under extreme conditions, suitable for aerospace and marine applications.
Inco Nickel 825
More resistant to corrosion: Organic acids (such as formic acid or acetic acid) and certain chloride environments.
Reason: Higher copper content enhances resistance to reducing acids.
Advantages: Suitable for moderately corrosive environments, economical, good mechanical properties, and strong corrosion resistance.
Chemical Composition Comparison: Inconel 600 vs. Incoloy 825
| Element | Inconel 600 (%) | Incoloy 825 (%) |
|---|---|---|
| Nickel (Ni) | ≥ 72.0 | 38.0 - 46.0 |
| Chromium (Cr) | 14.0 - 17.0 | 19.5 - 23.5 |
| Iron (Fe) | 6.0 - 10.0 | ≥ 22.0 |
| Molybdenum (Mo) | - | 2.5 - 3.5 |
| Copper (Cu) | ≤ 0.5 | 1.5 - 3.0 |
| Carbon (C) | ≤ 0.15 | ≤ 0.05 |
| Manganese (Mn) | ≤ 1.0 | ≤ 1.0 |
| Silicon (Si) | ≤ 0.5 | ≤ 0.5 |
| Sulfur (S) | ≤ 0.015 | ≤ 0.03 |
| Aluminum (Al) | - | ≤ 0.2 |
| Titanium (Ti) | - | 0.6 - 1.2 |
The choice of material suitable for acidic media depends primarily on its corrosion resistance, durability, and performance characteristics. Incoloy 825 and Alloy 625 seamless tubing are several commonly used materials for manufacturing vertical conductive wires. Gnee Steel has special properties that make it very suitable for use in acidic media, but there are also differences between the two.
Mechanical Properties Comparison: Inconel 600 vs. Incoloy 825
| Property | Inconel 600 (Annealed) | Incoloy 825 (Annealed) |
|---|---|---|
| Tensile Strength | 550-655 MPa (80-95 ksi) | 586-689 MPa (85-100 ksi) |
| Yield Strength (0.2% Offset) | 240-310 MPa (35-45 ksi) | 241-345 MPa (35-50 ksi) |
| Elongation | 35-45% | 30-45% |
| Hardness (Brinell) | 150-220 HB | 150-210 HB |
| Density | 8.47 g/cm³ | 8.14 g/cm³ |
| Melting Range | 1370-1425°C (2500-2600°F) | 1370-1400°C (2500-2550°F) |
| Elastic Modulus | 214 GPa (31×10⁶ psi) | 196 GPa (28.4×10⁶ psi) |
| Poisson's Ratio | 0.29 | 0.28 |
Performance of Incoloy 825 and Alloy 625 under Acidic Conditions
Incoloy 825 is a nickel-iron-chromium alloy containing a small amount of molybdenum and belongs to the mainstream steel series. This material is known for its excellent resistance to reduction and oxidation, making it one of the ideal choices when corrosion is a concern. Furthermore, Alloy 625 is also a nickel-chromium-molybdenum alloy with similar corrosion resistance in acidic media. While its composition may make it superior to Incoloy 825 in certain situations, better performance is required under other conditions.
Corrosion Resistance Comparison: Inconel 600 vs. Incoloy 825
| Corrosion Type/Environment | Inconel 600 | Incoloy 825 |
|---|---|---|
| Oxidizing Environments | Excellent | Good |
| Reducing Environments | Fair | Excellent |
| Chloride Stress Corrosion Cracking | Good | Excellent |
| Sulfuric Acid | Good (dilute) | Excellent (all concentrations) |
| Phosphoric Acid | Good | Excellent |
| Nitric Acid | Excellent | Good |
| Hydrochloric Acid | Poor | Good (dilute, aerated) |
| Hydrofluoric Acid | Poor | Fair |
| Caustic Solutions | Excellent | Excellent |
| Seawater/Marine | Good | Excellent |
| Pitting Resistance | Good | Excellent |
| Crevice Corrosion | Good | Excellent |
| High-Temperature Oxidation | Excellent (up to 1177°C) | Good (up to 816°C) |
| Carburization | Good | Fair |
| Nitridation | Good | Fair |
Which alloy is better suited for high strength and durability in acidic environments-Incoloy 825 or Alloy 625?
Both Incoloy 825 and Alloy 625 are suitable for acidic media applications. However, Incoloy 825 alloy is favored for its toughness, durability, and corrosion resistance, maintaining excellent performance even in highly challenging industrial environments. Several factors need to be considered when choosing between these two materials, including the pH of the environment, the application scenario, and the required corrosion resistance. If the acidic medium is too corrosive for ordinary seamless steel pipes to withstand, understanding these factors will help you compare different types of materials and choose the one best suited for such media.
Choosing Between Incoloy 825 Seamless Pipes and Alloy 625 in Acidic Environments
Both Incoloy 825 and Alloy 625 are suitable for acidic environments, but Incoloy 825 offers superior performance and stronger corrosion resistance. You need to choose the material best suited for your application and with the best corrosion resistance, so evaluate both materials and compare them according to your needs. Choosing the right material ensures your equipment remains in perfect condition for a long time. As suppliers who sell rubber liners and rubber tanks guarantee, these materials ensure your equipment always performs optimally, even in highly corrosive acidic media. Therefore, choose Gnee Steel to meet all your seamless pipe needs and provide the highest quality products for your industrial applications.
Why Choose Gnee as Your Nickel-Based Alloy Supplier
✅ Over 18 years of export experience, products sold to more than 80 countries
✅ Certified by ISO, SGS, and BV
✅ Global inventory of Inconel, Hastelloy, Incoloy, and Monel alloy tubing, plates, and bars
✅ Custom processing services available – including cutting, polishing, CNC machining, and packaging
✅ Fast delivery within 7-15 days, supported by global logistics partners
📦 Packaging and Shipping
All stainless steel products are packaged using the following methods:
Wooden pallets or crates
Moisture-proof packaging
Labels with furnace number, standard, and size labels
Shipped worldwide by sea, air, or express
