Nitronic 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.
What Nitronic 60 is.
Nitronic 60 (UNS S21800) is an austenitic stainless alloyed with about 4 percent silicon, 8 percent manganese and 0.13 percent nitrogen. The silicon and manganese change how the surface deforms, so the alloy resists the cold welding that makes ordinary stainless threads gall, and it wears far better than 304 or 316 in metal-to-metal contact. Corrosion resistance is between 304 and 316, and strength is above both at 95 ksi annealed.
We machine Nitronic 60 nuts, valve stems, bushings, pins and wear parts from certified A276 bar. Nuts in Nitronic 60 are the standard fix for galling on 304, 316 and Nitronic 50 studs. For pressure bolting the alloy is ASTM A193 B8S with A194 8S nuts.
Chemical composition.
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Carbon | C | — | 0.10 |
| Manganese | Mn | 7.0 | 9.0 |
| Phosphorus | P | — | 0.060 |
| Sulfur | S | — | 0.030 |
| Silicon | Si | 3.5 | 4.5 |
| Chromium | Cr | 16.0 | 18.0 |
| Nickel | Ni | 8.0 | 9.0 |
| Nitrogen | N | 0.08 | 0.18 |
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 | 95 | 50 | 35 | 55 | 241 HBW max |
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 60 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 60 fasteners we make.
Every item is manufactured to your drawing or standard in Nitronic 60, imperial or metric, with an EN 10204 3.1 certificate.
What is Nitronic 60?
Nitronic 60 was developed to solve galling. Austenitic stainless steels cold weld to each other under thread pressure because their surfaces are ductile and their oxide films are thin; silicon and manganese in Nitronic 60 alter the surface so that it work-hardens and shears instead of welding. The result is a stainless that can be threaded onto another stainless dry, repeatedly, without seizing, and that wears about ten times better than 304 in sliding contact.
Using Nitronic 60 to stop galling
- Pair a 304, 316 or Nitronic 50 stud with a Nitronic 60 nut; the dissimilar surfaces will not gall.
- Use it for valve stems, gate guides and bushings where lubricants are prohibited, as in food, pharmaceutical and oxygen service.
- Corrosion resistance sits between 304 and 316, so keep it out of the most severe chloride service.
- Strength is above 316 but below Nitronic 50; use Nitronic 50 for the loaded member and Nitronic 60 for the mating part.
Testing, certification and marking
- Tensile and hardness tested per lot on the finished product
- Grade or marking symbol B8S 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
ASTM A193 Grade B8S (Nitronic 60)
Nitronic 60 bolting — the anti-galling stainless: 95 ksi, non-magnetic, and threads that will not seize against other stainless steels.
ASTM A276 bar · ASTM A193 B8R boltsNitronic 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.
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.