Inconel 690 vs 600: Nuclear High-Temp Service
Date: 2026年9月13日 Categories: News Views: 263
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 Inconel 690 and Inconel 600?
Inconel 690 (UNS N06690) and Inconel 600 (UNS N06600) are both nickel-chromium alloys, but 690 carries nearly 30% chromium versus 600's ~15.5%. That doubling of chromium is the entire story: 690 was developed because 600 suffered stress-corrosion cracking (SCC) in high-temperature high-purity water in nuclear steam generators. 690's higher chromium makes it dramatically more resistant to SCC in caustic and primary-water environments. Today 690 is the standard for nuclear steam generator tubing; 600 remains widely used for industrial furnace and heat-treat applications.
Composition Comparison (wt.%)
| Element | Inconel 690 (N06690) | Inconel 600 (N06600) |
|---|---|---|
| Nickel | 58 min | 72 min |
| Chromium | 27-31 | 14-17 |
| Iron | 7-11 | 6-10 |
| Carbon | 0.05 max | 0.15 max |
| Aluminum | -- | -- |
Corrosion Performance Comparison
| Environment | Inconel 690 | Inconel 600 | Better |
|---|---|---|---|
| High-purity water SCC (350C) | Excellent | Susceptible | 690 |
| Caustic SCC | Excellent | Susceptible | 690 |
| Chloride SCC | Excellent | Good | 690 |
| Oxidation (1000C+) | Good | Good | Tie |
| Carburization | Good | Excellent | 600 |
| Chlorination | Good | Excellent | 600 |
| Nitric acid / HNO3 | Excellent | Good | 690 |
Mechanical Properties (Annealed, RT)
| Property | Inconel 690 | Inconel 600 |
|---|---|---|
| Tensile Strength | 585-760 MPa | 550-690 MPa |
| Yield Strength | 240-345 MPa | 205-345 MPa |
| Elongation | 30-45% | 35-50% |
| Thermal expansion | Lower | Higher |
Which One for Your Application?
| Application | Best Choice | Why |
|---|---|---|
| Nuclear steam generator tubes | 690 | SCC resistance in primary water |
| Nuclear reactor internals | 690 | Proven pedigree |
| HNO3 / nitric acid service | 690 | Higher Cr |
| Industrial furnace fixtures | 600 | Carburization resistance |
| Heat-treat retorts | 600 | Cost + performance |
| Thermocouple sheathing | 600 | Formability |
Price Comparison (2026, EXW)
| Form | Inconel 690 | Inconel 600 |
|---|---|---|
| Tube | \$48-72/kg | \$38-58/kg |
| Plate | \$42-65/kg | \$28-42/kg |
| Round Bar | \$45-68/kg | \$30-45/kg |
690 costs 25-40% more due to higher chromium and nuclear-grade quality requirements.
FAQ
Q1: Why was Inconel 690 developed?
To solve 600's stress-corrosion cracking problems in nuclear steam generator tubing.
Q2: What are the UNS numbers?
N06690 = Inconel 690; N06600 = Inconel 600.
Q3: Can 690 replace 600?
Yes for SCC-prone and oxidizing acid service, at higher cost. For carburizing/chlorinating atmospheres, 600 remains better.
Q4: Which has better oxidation resistance?
Similar; both perform well to ~1100C.
Q5: Which is more expensive?
690 is typically 25-40% more expensive.
Q6: Which for nitric acid?
690 — higher chromium improves oxidizing acid resistance.
Q7: What does Shanghai Hangbo supply?
Both grades in tubes, plates, bars, 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
Product Forms: Bars(6-500mm) | Tubes(OD 6-610mm) | Plates(0.1-100mm) | Forgings | Welded Pipes | Fittings | Wire(0.05-10mm) | Strip(0.02-4.0mm)
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