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Inconel 625 and Inconel 825 are both high-performance nickel-based alloys widely used in corrosive and high-temperature environments. While they share some similarities in application, their chemical compositions, mechanical properties, and market prices differ significantly. Understanding the price difference between Inconel 625 and Inconel 825 requires examining their alloy content, production costs, global demand, and typical industrial uses. Below is a detailed comparison to help buyers and engineers make informed procurement decisions.
Chemical Composition Comparison
One key factor influencing the price of each alloy is its chemical makeup. Inconel 625 contains more expensive alloying elements such as molybdenum and niobium, which contribute to its higher price.
| Element | Inconel 625 (%) | Inconel 825 (%) |
|---|---|---|
| Nickel (Ni) | 58.0 min | 38.0–46.0 |
| Chromium (Cr) | 20.0–23.0 | 19.5–23.5 |
| Iron (Fe) | 5.0 max | Balance |
| Molybdenum (Mo) | 8.0–10.0 | 2.5–3.5 |
| Niobium (Nb + Ta) | 3.15–4.15 | — |
| Copper (Cu) | — | 1.5–3.0 |
| Titanium (Ti) | ≤0.40 | 0.6–1.2 |
Price Comparison (Estimated Market Rates)
Inconel 625 is generally more expensive than Inconel 825 due to its higher content of molybdenum and niobium, which are costly alloying elements. The prices fluctuate based on market supply and demand, production origin, form (bar, plate, pipe), and quantity ordered.
| Form | Inconel 625 Price (USD/kg) | Inconel 825 Price (USD/kg) |
|---|---|---|
| Rod / Bar | USD 95 – 125 | USD 50 – 70 |
| Sheet / Plate | USD 90 – 120 | USD 48 – 65 |
| Pipe / Tube | USD 100 – 130 | USD 55 – 75 |
Cost Factors Affecting Price Differences
Several factors explain why Inconel 625 is priced significantly higher than Inconel 825:
| Factor | Inconel 625 | Inconel 825 |
|---|---|---|
| Alloying Content | High (Mo, Nb) | Moderate (Ti, Cu) |
| Corrosion Resistance | Superior (especially seawater, acid) | Excellent (especially sulfuric acid) |
| Temperature Capability | Up to 980°C | Up to 540°C |
| Manufacturing Cost | Higher | Lower |
| Market Demand | High in oil & gas, marine | Moderate in chemical process industry |
Typical Applications and Usage Environment
Both alloys are chosen based on cost-performance balance. While Inconel 625 offers better overall resistance to aggressive corrosion and high temperatures, Inconel 825 is often sufficient for less severe environments at a more economical price point.
| Industry | Inconel 625 Applications | Inconel 825 Applications |
|---|---|---|
| Oil & Gas | Flexible risers, piping, subsea equipment | Tubulars, acid gas equipment |
| Marine | Seawater heat exchangers, pumps | Condenser tubes |
| Chemical Processing | Reactors, scrubbers | Pickling tank heaters |
| Aerospace | Jet engine components | — |
Which Alloy to Choose?
If your application requires resistance to high temperatures and very aggressive corrosion (e.g., seawater, acidic solutions at elevated pressure), Inconel 625 is the superior choice despite its higher cost. However, for cost-sensitive projects with moderate corrosion requirements and lower temperature exposure, Inconel 825 offers a more economical and sufficient solution.
Frequently Asked Questions
1. Why is Inconel 625 more expensive than Inconel 825?
Because Inconel 625 contains higher levels of molybdenum and niobium, which significantly increase both corrosion resistance and material cost.
2. Is Inconel 825 suitable for high-temperature environments like Inconel 625?
No, Inconel 825 is generally used below 540°C, while Inconel 625 can withstand temperatures up to 980°C, making it better for thermal applications.
3. Can Inconel 825 be used in seawater environments?
Yes, Inconel 825 performs well in seawater but not as extensively or reliably as Inconel 625, which is optimized for marine and offshore corrosion resistance.