Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Nitronic 60 Galling Resistance (ASTM G98, 5 to 10x vs 304 / 316L)
Nitronic 60 galling resistance is the alloy's primary USP. Threshold galling stress per ASTM G98 self-mated button-on-block test is 350 to 500 MPa for Nitronic 60 versus 35 to 70 MPa for 304 / 316L self-mated. The 5 to 10 times improvement is achieved through the high-Mn-Si-N chemistry that builds a tenacious surface oxide and reduces stacking-fault energy to favor planar slip without exposing virgin austenite under contact pressure.
TorqBolt stocks Nitronic 60 (UNS S21800) at our Mumbai head office and Rajkot production plant. Each consignment ships with EN 10204 3.1 mill test certification by default and 3.2 dual-witnessed inspection (Lloyds, TUV, DNV, BV) on request. Contact info@torqbolt.com or +91-22-66157017 for sized stock and lead time.
Galling Mechanism and Test Method
Galling is cold-welding of metal surfaces under sliding contact, NOT a corrosion process. The surface oxide breaks down under contact pressure, virgin metal exposes, and cold-welds to the mating surface. As sliding continues the bonded spot tears, ripping material from one surface and depositing it on the other.
ASTM G98 test method: button-on-block configuration, axial-load + rotational-displacement, threshold-galling-stress reported as the load at which surface damage initiates. Self-mated and dissimilar-mated combinations both standard.
Nitronic 60 mechanism: 7-9 percent Mn lowers stacking-fault energy enough to favor planar dislocation slip; 3.5-4.5 percent Si promotes a tenacious Cr-Si surface oxide; 0.08-0.18 percent N solid-solution-strengthens to raise work-hardening threshold. All three elements together produce the anti-galling property; removing any one collapses the effect.
For the broader anti-galling story see stainless steel galling failure and anti-galling applications.
Chemistry — UNS S21800
Cr 16-18 / Mn 7-9 / Ni 8-9 / Si 3.5-4.5 / N 0.08-0.18 / C ≤0.10. See full element ranges with single and aggregate limits →
Nitronic 60 Mechanical Properties
Solution-annealed and cold-worked condition mechanical properties per ASTM A276, ASTM A479, and AMS 5848:
| Property | Solution Annealed | Cold-Worked HS |
|---|---|---|
| Yield Strength (0.2% offset) | 380 MPa (55 ksi) min | 620 MPa (90 ksi) min |
| Tensile Strength | 655 MPa (95 ksi) min | 860 MPa (125 ksi) min |
| Elongation (in 4D) | 35% min | 15% min |
| Hardness | 95 HRB max (~210 HB) | 30 HRC max |
| Impact (Charpy V at -196 C) | 54 J min | - |
| Density | 7.62 g/cc | 7.62 g/cc |
See yield strength, tensile properties, hardness, and density for cold-work curves and temperature-derated allowables.
Galling Resistance vs 304 / 316L (ASTM G98)
The primary reason buyers specify Nitronic 60. Threshold galling stress per ASTM G98 button-on-block self-mated test:
| Self-Mated Pair | Threshold Galling Stress (ASTM G98) | Relative |
|---|---|---|
| 304 / 304 | 35 to 70 MPa | 1x baseline |
| 316L / 316L | 35 to 70 MPa | 1x baseline |
| Nitronic 50 / Nitronic 50 | 175 to 275 MPa | 3-5x |
| Nitronic 60 / Nitronic 60 | 350 to 500 MPa | 5-10x |
Where threshold stress exceeds the applied contact stress, galling does not initiate. For 316L bolted joints at typical preload, contact stress routinely exceeds 70 MPa, so galling DOES initiate. Nitronic 60 raises the threshold above typical preload contact stress, so galling does NOT initiate. See galling resistance and galling failure mechanism for the full mechanism.
Heat Treatment
Solution anneal only at 1900-1950°F followed by water quench. No precipitation hardening response. See full heat treatment specification →
Welding
Matching filler ER218 per AMS 5847. GTAW, GMAW, and SMAW all qualified. No PWHT required for typical thicknesses. See full welding procedure →
Material Selection
Nitronic 60 wins for anti-galling at high temperature where 304/316L gall. Stellite is harder but brittle. vs 316L · vs Nitronic 50 · austenitic context →
Nitronic 60 Applications by Industry
- Marine and offshore, anti-galling bolting and deck hardware.
- Oil and gas, subsea wellhead, NACE MR0175 sour service, christmas-tree fasteners.
- Nuclear, valve trim, pump shafts, reactor coolant bolting.
- Food processing, FDA-acceptable austenitic, sanitary fittings, mixer paddles.
- Cryogenic, LNG hardware, austenitic stability to -196 C.
- Pump and rotating equipment, shafts and bushings under sliding seal contact.
- Valve stems, gate / globe valve stems under pressure cycling.
- Anti-galling general applications, cross-industry summary.
Related Nitronic 60 Forms and Fasteners
- Bar: round bar, hex bar, square bar, flat bar.
- Plate, sheet, forgings: plate, sheet, forgings.
- Wire and tubing: wire, spring wire, tubing, seamless pipe.
- Bolts: hex bolts, stud bolts, anchor bolts, socket head cap screws.
- Nuts: hex nuts, heavy hex nuts, lock nuts, jam nuts.
- Pins and inserts: dowel pins, clevis pins, bushings, Helicoil thread inserts.
- Catalog: full Nitronic 60 fastener portfolio, anti-galling fasteners.
Request a Quote
For Nitronic 60 stock with verified galling resistance certification, Contact the TorqBolt QA-QC team at info@torqbolt.com or +91-22-66157017. We respond within 24 hours with sized stock availability, lead time, and EN 10204 3.1 / 3.2 MTC documentation samples.
Frequently Asked Questions
What is the Nitronic 60 galling resistance?
See the values in the table above. The galling resistance of Nitronic 60 is one of the property metrics that distinguishes it from 304 / 316L.
Why does Nitronic 60 galling resistance matter?
For design engineering decisions, galling resistance directly affects component sizing, service envelope, and material substitution choices.
How is galling resistance verified?
Standard test methods per ASTM. Mill test certificate (EN 10204 3.1) reports the measured value for the heat lot.
What is the temperature dependence?
Nitronic 60 retains useful properties from -196 C cryogenic to ~815 C upper service temperature. Above 540 C check sigma-phase precipitation envelope.
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