Summary
In scrap, the two are often mixed because they look and read alike. Shafts, springs and oil-well tools are usually K-500; piping, valves and heat exchanger parts are usually 400. A light-element reading confirms which is which.
Side by Side
| Monel 400 | Monel K-500 | |
|---|---|---|
| Strengthening | Solid solution, cold work | Age-hardened (γ′) |
| Typical service | Seawater piping, valves, HF units | Pump and propeller shafts, oil-well tools, springs |
| Magnetism | Weakly magnetic near room temperature | Non-magnetic |
| Specification | ASTM B127, B164, B165 | ASTM B865 |
Composition Compared
Nominal compositions compared element by element. Change either grade to compare others.
On the XRF
Switch the grade to see how the fingerprint changes. See how XRF sorts nickel alloys.
FAQ
What is the main difference between Monel 400 and Monel K-500?
Monel K-500 is Monel 400 with about 2.7% aluminium and 0.6% titanium added, so it can be age-hardened to much higher strength. Their nickel-copper base is almost the same, so a basic XRF struggles to tell them apart; aluminium must be confirmed with a light-element XRF setup or OES.
Can Monel 400 and Monel K-500 scrap be mixed?
No. Keep them separate. A melter buying either one needs its chemistry to stay within the grade’s limits, and mixing can mean a re-sort or a different valuation.