Nitronic 50 and Nitronic 60 are both austenitic stainless steels, but they serve very different purposes. One is built for strength and corrosion, while the other is specifically for preventing wear and galling. Choosing the right one depends on whether your part will be sitting in a harsh chemical environment or rubbing against another metal surface. This guide provides a detailed comparison to help you choose the right Nitronic grade for your application.
Nitronic 50 (UNS S20910)
Nitronic 50, or XM-19 stainless steel, is a nitrogen-strengthened steel. It has about double the yield strength of 316L. It stays non-magnetic even after heavy cold work, which makes it useful for applications where you need to avoid magnetic interference.
Key Nitronic 50 properties are provided below.
Nitronic 50 Chemical Composition
| Element |
Percentage |
| Chromium |
20.5–23.5% |
| Nickel |
11.5–13.5% |
| Manganese |
4.0–6.0% |
| Molybdenum |
1.5–3.0% |
| Silicon |
1.0% max |
| Nitrogen |
0.20–0.40% |
| Carbon |
0.06% max |
| Iron |
Balance |
Nitronic 50 Mechanical Properties
| Property |
Value |
| Ultimate Tensile Strength |
806 MPa (117 ksi) |
| Yield Strength (0.2% offset) |
413 MPa (60 ksi) |
| Elongation |
35% min |
| Hardness |
Up to 293 HB |
Nitronic 60 (UNS S21800)
Nitronic 60 (Alloy 218) is the choice for wear and galling resistance. It has high silicon (4%) and manganese (8%) levels. These elements help the metal resist sticking or tearing when it slides against other parts.
Important Nitronic 60 properties are mentioned below.
Nitronic 60 Chemical Composition
| Element |
Percentage |
| Chromium |
16.0–18.0% |
| Nickel |
8.0–9.0% |
| Manganese |
7.0–9.0% |
| Silicon |
3.5–4.5% |
| Nitrogen |
0.08–0.18% |
| Molybdenum |
0.75% max |
| Carbon |
0.10% max |
| Iron |
Balance |
Nitronic 60 Mechanical Properties
| Property |
Value |
| Ultimate Tensile Strength |
655 MPa (95 ksi) |
| Yield Strength (0.2% offset) |
379 MPa (55 ksi) |
| Elongation |
35% min |
| Hardness |
Up to 241 HB |
Key Differences Between Nitronic 50 and Nitronic 60
The key difference between Nitronic 50 and Nitronic 60 is explained below.
Corrosion Resistance
Nitronic 50 is the preferred choice here. It has more chromium, nickel, and molybdenum, which protect it from pitting and crevice corrosion. It works well in seawater and chloride environments. Nitronic 60 is closer to 304 or 316 stainless steel in terms of corrosion. It’s suitable for some uses, but it won’t hold up as well as Nitronic 50 in aggressive chemicals.
Galling and Wear
Nitronic 60 is the better option for this. The silicon and manganese prevent parts from galling even in the annealed condition. Nitronic 50 doesn’t have these special wear properties, so it’s not the best for sliding parts.
Temperature and Mechanical Strength
Nitronic 50 is stronger overall, with a yield strength of 413 MPa compared to 379 MPa for Nitronic 60. However, Nitronic 60 handles heat better. It stays effective up to 540°C (1000°F), while Nitronic 50 is usually capped around 315°C (600°F) for most applications.
| Property |
Nitronic 50 |
Nitronic 60 |
| Tensile Strength |
806 MPa (117 ksi) |
655 MPa (95 ksi) |
| Yield Strength |
413 MPa (60 ksi) |
379 MPa (55 ksi) |
| Elongation |
35% |
35% |
Magnetic Properties
Both Nitronic 50 and Nitronic 60 are fully austenitic and remain non-magnetic even after severe cold working. This is an advantage over standard 300 series stainless steels, which can become slightly magnetic after cold deformation.
Comparison Summary Table
Nitronic 50 vs Nitronic 60 comparison is provided below.
| Feature |
Nitronic 50 (S20910) |
Nitronic 60 (S21800) |
| Primary strength |
Corrosion resistance |
Galling/wear resistance |
| Nickel content |
11.5–13.5% |
8.0–9.0% |
| Chromium content |
20.5–23.5% |
16.0–18.0% |
| Silicon content |
1.0% max |
3.5–4.5% |
| Manganese content |
4.0–6.0% |
7.0–9.0% |
| Molybdenum |
1.5–3.0% |
0.75% max |
| Tensile Strength |
117 ksi |
95 ksi |
| Max service temp |
~315°C (600°F) |
~540°C (1000°F) |
| Galling resistance |
Standard |
Excellent |
| Pitting resistance |
Excellent |
Good |
| Magnetic after cold work |
No |
No |
Applications of Nitronic 50:
- Boat propeller shafts and marine fasteners.
- Oil and gas hardware used underwater.
- Pumps and valves in chemical plants.
- Cryogenic parts (it stays tough in the cold).
Nitronic 50 round bars are commonly stocked for these applications.
Applications of Nitronic 60:
- Valve seats and stems that come in contact with each other.
- Pump wear rings and shaft sleeves.
- Fasteners that might gall during tightening.
- Pins and bushings in moving machinery.
Welding Nitronic 50 and Nitronic 60
Both can be welded with standard methods. For Nitronic 50, use matching filler or
ER308L/309L. For Nitronic 60, use matching filler or ER309L. You usually don’t need to preheat these metals.
How to Choose Between Nitronic 50 and Nitronic 60
Deciding between these two usually comes down to one main question: is the part going to corrode or is it going to wear out from friction?
- Pick Nitronic 50 if you are working in marine environments or with harsh chemicals. It is stronger and resists pitting much better than Nitronic 60.
- Pick Nitronic 60 if you have metal parts sliding against each other. It prevents galling (where metal surfaces gall).
- Check the temperature. If your part gets hotter than 315°C (600°F), Nitronic 60 is usually the better choice because it holds its properties at higher temperatures.
Both alloys are more expensive than standard 300-series stainless steel. You should only pay the extra cost if 316L isn’t strong enough or keeps failing due to corrosion or galling.
Frequently Asked Questions
Can Nitronic 60 replace Nitronic 50?
Not in most situations. If corrosion is the main issue, then it is not recommended to use Nitronic 60 instead of Nitronic 50. Nitronic 50 has more nickel and molybdenum. If you swap it for Nitronic 60 in a high-chloride environment, the part will likely fail much sooner.
Is Nitronic 60 actually better for galling than 316?
Yes. 316 stainless is known for galling and seizing up, especially in threaded bolts. Nitronic 60 was made specifically to prevent that from happening.
Are Nitronic alloys easy to weld?
Yes. You can use standard processes like TIG or MIG. Use the right filler metal, and you won’t usually need to preheat the material.
What ASTM standards cover Nitronic alloys?
Nitronic 50 is covered under ASTM A182 (forgings), ASTM A276 (bars), ASTM A479 (bars for pressure vessels), and ASTM A240 (plate/sheet). Nitronic 60 is covered under similar ASTM specifications with its UNS S21800 designation.
Which one is better for marine applications?
Nitronic 50. It’s much more resistant to chloride pitting, crevice corrosion, and stress corrosion cracking.
Conclusion
Nitronic 50 and 60 are both high-end steels, but they serve different applications. Nitronic 50 is for high-strength, high-corrosion jobs like boat shafts or chemical tanks. Nitronic 60 is for parts that move or slide against each other, where you want to avoid wear and galling. If you know whether the biggest threat to your application is rust or friction, the choice is fairly simple.
