Nitronic 50® Stainless Steel (UNS S20910, XM-19)
Nearly twice the yield strength of 316 with better corrosion resistance, non-magnetic even after cold work — the marine and sour-service austenitic for shafts, valves and high-strength bolting.
What Nitronic 50 is.
Nitronic 50 (UNS S20910, XM-19) is a nitrogen-strengthened austenitic stainless steel with 22 percent chromium, 12 percent nickel, 2 percent molybdenum and additions of niobium and vanadium. Nitrogen in solid solution nearly doubles the yield strength of 316 while raising the pitting resistance above it, and the austenite is stable enough to stay non-magnetic after heavy cold work. In the high-strength condition, hot rolled and not annealed, it reaches 135 ksi tensile in bar to 2 in.
We machine Nitronic 50 shafts, valve components, studs and bolts from certified A276 bar. For pressure bolting the same alloy is ASTM A193 B8R with A194 8R nuts.
Chemical composition.
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Carbon | C | — | 0.06 |
| Manganese | Mn | 4.0 | 6.0 |
| Phosphorus | P | — | 0.045 |
| Sulfur | S | — | 0.030 |
| Silicon | Si | — | 1.00 |
| Chromium | Cr | 20.5 | 23.5 |
| Nickel | Ni | 11.5 | 13.5 |
| Molybdenum | Mo | 1.50 | 3.00 |
| Nitrogen | N | 0.20 | 0.40 |
| Niobium | Nb | 0.10 | 0.30 |
| Vanadium | V | 0.10 | 0.30 |
Values per ASTM A276/A276M-17 Tables 1 and 2 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Mechanical properties.
| Condition and nominal diameter (in.) | Tensile strength, min (ksi) | Yield strength 0.2% offset, min (ksi) | Elongation, min (%) | Reduction of area, min (%) | Hardness |
|---|---|---|---|---|---|
| Condition A (annealed) — all | 100 | 55 | 35 | 55 | — |
| As hot rolled (high strength) — 2 and under | 135 | 105 | 20 | 50 | — |
| As hot rolled — over 2 to 3 | 115 | 75 | 25 | 50 | — |
| As hot rolled — over 3 to 8 | 100 | 60 | 30 | 50 | — |
Values per ASTM A276/A276M-17 Tables 1 and 2 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Specifications that apply.
How Nitronic 50 ships from Houston.
- Hex and heavy hex bolts and cap screws
- Full-thread studs and threaded rod
- Socket head cap and set screws
- Hex, jam and lock nuts
- Washers and spacers
- Machined components from certified bar
Nitronic 50 fasteners we make.
Every item is manufactured to your drawing or standard in Nitronic 50, imperial or metric, with an EN 10204 3.1 certificate.
What is Nitronic 50?
Nitronic 50 is an austenitic stainless steel that uses nitrogen, rather than cold work, for strength. About 0.3 percent nitrogen in solution raises the annealed yield strength to 55 ksi minimum, almost twice the 30 ksi of 316, and the tensile to 100 ksi against 75, and the alloy's chromium, molybdenum and nitrogen together give it better pitting resistance than 316 as well. Because the austenite is very stable it stays non-magnetic after machining and cold work, which matters for naval and instrumentation applications.
Nitronic 50 or duplex 2205?
Both give strength and chloride resistance above 316. Duplex is stronger still and less costly, but it is magnetic, loses toughness below about −50 °F and above 600 °F, and is harder to machine. Nitronic 50 stays non-magnetic, is tough from cryogenic temperatures to 1200 °F, and machines like a stiff 316. Choose duplex for flanges and structures in the temperature band it tolerates, Nitronic 50 for shafts, non-magnetic hardware and wide temperature ranges.
Testing, certification and marking
- Tensile and hardness tested per lot on the finished product
- Grade or marking symbol B8R for A193 bolting and manufacturer's identification on every piece
- EN 10204 3.1 material test report with heat number and chemistry; 3.2 witness available
- PMI verification and intergranular corrosion testing (ASTM A262) arranged on request
Recent Nitronic 50 jobs.
ASTM A193 Grade B8R (Nitronic 50 / XM-19)
Nitronic 50 bolting — twice the yield strength of 316 with better seawater corrosion resistance and no loss of ductility, non-magnetic even after cold work.
ASTM A276 bar · ASTM A193 B8S boltsNitronic 60® Stainless Steel (UNS S21800)
The anti-galling stainless: silicon and manganese give it a wear-resistant surface, so nuts and threads assemble dry without seizing — for valve stems, nuts and repeatedly assembled joints.
ASTM A276 bar · ASTM F593 bolts316 Stainless Steel (UNS S31600)
The marine and chemical-plant stainless: 2 to 3 percent molybdenum for pitting and crevice resistance in chlorides, with the same strength tables as 304.