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 Anti-Galling Applications - Where Stainless Galling Matters
Nitronic 60 anti-galling applications span every industry where 304 / 316L stainless hardware retires early from the cold-welding adhesion failure mode. The high-Mn-Si-N chemistry raises threshold galling stress per ASTM G98 by 5 to 10 times over 304 / 316L self-mated, eliminating thread tearing on bolted joints, valve-stem seizing, shaft scoring against bushings, and Helicoil insert galling. This page summarizes the canonical anti-galling use cases across marine, oil and gas, nuclear, food processing, pharma, instrumentation, and cryogenic service.
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.
Service Envelope for Anti-Galling Applications
Galling is the dominant failure mode of austenitic stainless steel hardware in sliding-contact and threaded service. Nitronic 60 was developed by Armco in the 1970s specifically to address this. The chemistry adds 7 to 9 percent manganese, 3.5 to 4.5 percent silicon, and 0.08 to 0.18 percent nitrogen to the austenitic stainless matrix. The result is roughly 5 to 10 times higher threshold galling stress versus 304 / 316L self-mated per ASTM G98 test method.
- Bolted joints, 316L bolts gall during makeup-breakout cycles. Nitronic 60 bolts install dry and tolerate 50+ cycles. See hex bolts and stud bolts.
- Threaded inserts, 304 Helicoils gall during installation. Nitronic 60 inserts install cleanly. See Helicoil thread inserts.
- Valve trim, gate-valve stems gall in 316L. Nitronic 60 valve stems eliminate the seizing. See valve stems.
- Shafts and bushings, sliding-contact bushings gall on 316L shafts. Nitronic 60 pair eliminates scoring. See pump shafts and bushings.
- Pins and clevises, repeated-disassembly pins gall in stainless. Nitronic 60 tolerates 50+ cycles. See dowel pins and clevis pins.
Target Components in Anti-Galling Applications
- Marine deck hardware bolting, davit hinges, propeller-shaft fasteners.
- Subsea wellhead jumper bolting, christmas-tree fasteners, downhole-tool studs.
- Nuclear reactor coolant pump bolting, valve-trim seats, control-rod-drive hardware.
- Food-processing mixer paddles, sanitary fittings, conveyor flights.
- Cryogenic LNG hardware, austenite stable to -196 C without transformation.
- Pharmaceutical mixing equipment, FDA-acceptable austenitic chemistry.
- Instrumentation MRI fixtures, naval mine-warfare hardware, non-magnetic permeability priority.
- Helicoil thread-insert installations in aluminum tooling, aerospace airframe assemblies.
Nitronic 60 Chemistry (UNS S21800 Element Ranges)
All Nitronic 60 product forms share the UNS S21800 chemistry envelope per ASTM A276 / A479 specification:
| Element | Min % | Max % | Typical % |
|---|---|---|---|
| Carbon (C) | - | 0.10 | 0.05 |
| Manganese (Mn) | 7.0 | 9.0 | 8.0 |
| Phosphorus (P) | - | 0.060 | 0.025 |
| Sulfur (S) | - | 0.030 | 0.010 |
| Silicon (Si) | 3.5 | 4.5 | 4.0 |
| Chromium (Cr) | 16.0 | 18.0 | 17.0 |
| Nickel (Ni) | 8.0 | 9.0 | 8.5 |
| Nitrogen (N) | 0.08 | 0.18 | 0.13 |
| Iron (Fe) | Balance | ||
The Mn-Si-N combination is the active anti-galling chemistry. See detailed chemical composition for residuals and trace-element envelope.
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
Nitronic 60 is austenitic and NOT precipitation-hardenable. Standard heat treatment cycle is solution anneal only:
- Solution Anneal, 1010 to 1120 C (1850 to 2050 F) for 30 to 60 minutes, water quench.
- Stress Relief (optional), 450 to 480 C (840 to 900 F) for 2 to 4 hours, air cool.
- Avoid 540 to 815 C range during cooldown, risk of sigma-phase precipitation. Quench fast through this range.
- Cold work is the only strengthening mechanism, HS condition reaches ~30 HRC with retained ductility.
Welding
Nitronic 60 is weldable by GTAW, GMAW, SMAW, and PAW processes. Nitronic 60 welding procedure uses matching filler ER218 per AMS 5847 (UNS S21880, cast variant). Key parameters:
- Matching filler ER218 preserves anti-galling chemistry in the weld bead.
- Preheat NOT required (austenitic).
- Interpass temperature below 150 C (300 F) to avoid sigma precipitation.
- Post-weld solution anneal for critical service; as-welded adequate for general.
- ER309L is a non-matching emergency substitute; expect reduced galling resistance in the weld bead.
Material Selection: Nitronic 60 vs 316L vs 304 vs Stellite 6
| Property | 304 | 316L | Nitronic 50 | Nitronic 60 | Stellite 6 |
|---|---|---|---|---|---|
| UNS | S30400 | S31603 | S20910 | S21800 | R30006 |
| Yield (MPa) | 205 | 170 | 380 | 380 | 620 |
| Galling (G98) | Poor | Poor | Moderate | Excellent | Outstanding |
| PREN | 19 | 24 | 36 | 18 | N/A |
| Cost (relative) | 1x | 1.2x | 2.5x | 2x | 15-25x |
| Cryogenic to -196 C | Yes | Yes | Yes | Yes | Yes |
Detailed pair-wise comparisons: Nitronic 60 vs 316L, Nitronic 60 vs 304, Nitronic 60 vs Nitronic 50, Nitronic 60 vs 17-4 PH, Nitronic 60 vs Stellite 6, Nitronic 60 vs Inconel 718, and Nitronic 60 vs duplex 2205.
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 hardware specified for anti-galling applications, 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
Why Nitronic 60 for anti-galling applications?
The anti-galling chemistry eliminates the dominant failure mode of 304 / 316L hardware in anti-galling applications. Specifically the threshold galling stress per ASTM G98 is 5 to 10 times higher self-mated.
What forms are typically specified?
Fasteners (hex bolts, stud bolts, hex nuts), shafts, bushings, valve trim, sliding-contact components. See full fastener portfolio for the catalog overview.
What certification is required for anti-galling applications?
Typically EN 10204 3.1 mill test certificate as standard, with 3.2 dual-witnessed inspection (Lloyds, TUV, DNV, BV) for safety-critical or regulatory-monitored components. NACE MR0175 compliance available where sour-service exposure is part of the envelope.
Alternative materials for anti-galling applications?
Duplex 2205 (better chloride resistance, moderate galling), Inconel 625 (high-temperature corrosion at much higher cost), Stellite 6 (extreme galling at 15 to 25 times the cost). Nitronic 60 is the stainless-price-point anti-galling specification.
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