Incoloy 825 vs 926: Acid & Seawater Service
Date: 2026年9月11日 Categories: News Views: 334
By Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier | ISO 9001:2015 | Est. 2012
Contact: sales@hangboalloy.com | hangbo@nickel-alloy.com | WhatsApp (Lisa): +86 13611656360
Quick Answer: What Is the Difference Between Incoloy 825 and Incoloy 926?
Incoloy 825 (UNS N08825) and Incoloy 926 (UNS N08926, also called 25-6MO) are both molybdenum-containing iron-nickel-chromium alloys for acid and seawater service, but 926 is the significantly more corrosion-resistant grade. 926 carries 6-7% Mo and ~0.2% N with higher chromium (19-21%), giving a PREN above 40 — versus 825's 2.5-3.5% Mo and PREN ~31. 926 therefore resists pitting and crevice corrosion in chlorides far better, while 825 remains the economical choice for sulfuric and phosphoric acid service. Rule: chloride/pitting risk → 926; sulfuric/phosphoric acid → 825.
Composition Comparison (wt.%)
| Element | Incoloy 825 (N08825) | Incoloy 926 (N08926) |
|---|---|---|
| Nickel | 38-46 | 24-26 |
| Chromium | 19.5-23.5 | 19-21 |
| Molybdenum | 2.5-3.5 | 6.0-7.0 |
| Copper | 1.5-3.0 | 0.5-1.5 |
| Nitrogen | -- | 0.15-0.25 |
| Iron | Balance (~30%) | Balance (~50%) |
| Titanium | 0.6-1.2 | -- |
Corrosion Performance Comparison
| Environment | Incoloy 825 | Incoloy 926 | Better |
|---|---|---|---|
| PREN value | ~31 | ~43 | 926 |
| Pitting in chlorides | Moderate | Excellent | 926 |
| Crevice corrosion (seawater) | Moderate | Excellent | 926 |
| H2SO4 (dilute) | Excellent | Excellent | 825 |
| H3PO4 (phosphoric) | Excellent | Good | 825 |
| Seawater (flowing) | Good | Excellent | 926 |
| Stress corrosion cracking (Cl-) | Good | Excellent | 926 |
Mechanical Properties (Annealed, RT)
| Property | Incoloy 825 | Incoloy 926 |
|---|---|---|
| Tensile Strength | 550-690 MPa | 650-850 MPa |
| Yield Strength | 240-345 MPa | 300-420 MPa |
| Elongation | 30-45% | 25-40% |
Which One for Your Application?
| Application | Best Choice | Why |
|---|---|---|
| Sulfuric acid piping | 825 | Proven acid resistance + cost |
| Phosphoric acid evaporators | 825 | Classic application |
| Seawater heat exchangers | 926 | Pitting/crevice resistance |
| Offshore firewater systems | 926 | Chloride SCC resistance |
| Flue gas desulfurization | 926 | Chloride + acid mix |
| Pickling lines | 825 | Acid service |
Price Comparison (2026, EXW)
| Form | Incoloy 825 | Incoloy 926 |
|---|---|---|
| Plate | \$22-34/kg | \$26-40/kg |
| Round Bar | \$20-32/kg | \$25-38/kg |
| Tube | \$28-42/kg | \$32-48/kg |
926 costs 15-25% more due to higher Mo and nitrogen alloying.
FAQ
Q1: Is Incoloy 926 better than 825?
For chloride pitting and seawater service, yes — PREN ~43 vs ~31. For sulfuric/phosphoric acid, 825 remains excellent and cheaper.
Q2: What is PREN?
Pitting Resistance Equivalent Number = %Cr + 3.3(%Mo) + 16(%N). 926 ≈ 43, 825 ≈ 31.
Q3: What are the UNS numbers?
N08825 = Incoloy 825; N08926 = Incoloy 926 (25-6MO).
Q4: Can 926 replace 825?
Yes in chloride service, with better pitting resistance. Re-check sulfuric acid duty.
Q5: Which is more expensive?
926 is typically 15-25% more expensive.
Q6: Which is better for seawater?
926, due to its higher molybdenum and nitrogen content.
Q7: What does Shanghai Hangbo supply?
Both grades in plates, bars, tubes, and fittings with EN 10204 3.1 certification. SGS/TUV/BV available.
Contact & Complete Product Range
Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier
Email: sales@hangboalloy.com | WhatsApp (Lisa): +86 13611656360 | www.nickel-alloy.com
All Grades
Ni: NI200-N6 | Monel: 400-502, K-500, R-405 | Inconel: 600-740H, X-750, 725 | Incoloy: 800-27-7MO | Hastelloy: C-276-HYBRID-BC1, N | Super Austenitic: 904L-AL-6XN | Chromium-Rich: Alloy 33 | High-Strength Stainless: Nitronic 50/60, PH13-8Mo | Chlorination: Alloy 45 | Nimonic: 75-263 | Haynes: 25-HR-160 | RA: 330/333 | Precision: 1J22-4J45 | High-Strength: 18Ni250-AerMet100 | Heating: Cr20Ni80/60 | Specialty: Alloy 20-602CA
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