Monel K-500 vs Monel 400 - Full Comparison of Strength, Hardness & Applications
Date: 2026年9月1日 Categories: News Views: 233
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 Monel K-500 and Monel 400?
Monel K-500 (UNS N05500) is the precipitation-hardened version of Monel 400 (UNS N04400). Both share the same ~67% Ni / ~30% Cu base and similar seawater corrosion resistance, but K-500 adds aluminum (2.3-3.15%) and titanium (0.35-0.85%), which precipitate Ni3(Al,Ti) during aging at 590-650C. This raises K-500's yield strength from ~240 MPa (400 annealed) to ~790 MPa (K-500 aged) and hardness from ~110 HB to ~300 HB. Choose K-500 for load-bearing seawater components (pump shafts, valve stems, drill collars); choose 400 for formability, welding, and cost (piping, sheathing, fasteners).
Composition Comparison (wt.%)
| Element | Monel K-500 (N05500) | Monel 400 (N04400) |
|---|---|---|
| Nickel (+Co) | 63-70 | 63-70 |
| Copper | 27-33 | 28-34 |
| Aluminum | 2.3-3.15 | -- |
| Titanium | 0.35-0.85 | -- |
| Iron | 2 max | 2.5 max |
| Manganese | 1.5 max | 2 max |
| Sulfur | 0.005 max | 0.024 max |
Mechanical Properties Comparison
| Property | Monel K-500 (Aged) | Monel 400 (Annealed) |
|---|---|---|
| Tensile Strength | 965-1100 MPa | 480-650 MPa |
| Yield Strength | 690-790 MPa | 170-240 MPa |
| Elongation | 20-30% | 35-50% |
| Hardness | 265-345 HB | 110-150 HB |
Corrosion Performance Comparison
| Environment | Monel K-500 | Monel 400 |
|---|---|---|
| Seawater (flowing) | Excellent | Excellent |
| Stagnant seawater | Risk of SCC | Good |
| Hydrofluoric acid (HF) | Excellent | Excellent |
| Caustic alkalis | Excellent | Excellent |
| Marine propeller shafts | Excellent (high strength) | Good (soft) |
Caution: K-500 in aged condition can be susceptible to stress corrosion cracking in stagnant seawater — always specify the correct heat treatment (e.g., age-hardened + stress-relieved for shafts).
Which One for Your Application?
| Application | Best Choice | Why |
|---|---|---|
| Pump shafts (seawater) | K-500 | Needs yield strength |
| Valve stems | K-500 | Wear + strength |
| Drill collars (oilfield) | K-500 | High torque |
| Heat exchanger tubing | 400 | Formable, weldable |
| Marine sheathing | 400 | Cost-effective |
| Fasteners (seawater) | K-500 | High strength |
Price Comparison (2026, EXW)
| Form | Monel K-500 | Monel 400 |
|---|---|---|
| Round Bar | \$38-58/kg | \$30-45/kg |
| Sheet/Plate | \$40-62/kg | \$32-48/kg |
K-500 costs 20-30% more due to Al/Ti alloying and aging heat treatment.
FAQ
Q1: Which is stronger, Monel K-500 or 400?
K-500, by 3-4x in yield strength (up to 790 MPa after aging).
Q2: Can Monel 400 be hardened?
Only by cold work. It has no precipitation-hardening response.
Q3: Is K-500 more corrosion resistant than 400?
Essentially equal in most marine/HF service, but K-500 needs care against SCC in stagnant seawater.
Q4: What is the K-500 aging treatment?
Solution anneal 980C, then age 590-650C for 8-16 hours.
Q5: What are the UNS numbers?
N05500 = Monel K-500; N04400 = Monel 400.
Q6: Which is better for pump shafts?
K-500 — its high yield strength resists bending and wear in seawater pumps.
Q7: Is K-500 more expensive?
Yes, typically 20-30% more than Monel 400.
Q8: What does Shanghai Hangbo supply?
Both grades in bars, plates, sheets, tubes, and forgings 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)
SGS/BV/TUV. www.nickel-alloy.com
