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 Heat Treatment (Solution Anneal, NOT PH)
Nitronic 60 heat treatment is solution-anneal only. The alloy is austenitic and NOT precipitation-hardenable. Standard cycle is 1010 to 1120 C (1850 to 2050 F) for 30 to 60 minutes followed by water quench. Slow cooling through the 540 to 815 C range risks sigma-phase precipitation that embrittles the alloy, so the quench must be fast through this temperature window.
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.
Heat Treatment Cycle Detail
Step 1, solution anneal at 1010 to 1120 C in furnace atmosphere or vacuum. The high temperature dissolves any prior chromium-carbide precipitate and locks the FCC gamma matrix. Hold time 30 to 60 minutes for full section through-heating.
Step 2, water quench from solution temperature. Rapid cooling preserves the dissolved-chromium state and prevents sigma-phase nucleation in the 540 to 815 C critical range. Furnace cooling or slow air cooling is NOT acceptable.
Optional step, stress-relief anneal at 450 to 480 C for 2 to 4 hours followed by air cool. This relieves cold-work-induced internal stress without affecting the solution-annealed yield-strength baseline. Useful after substantial cold-forming operations.
For welding-related heat treatment see welding procedure; for cold-work mechanical effects see mechanical properties.
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 stock with verified heat treatment 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 heat treatment?
See the values in the table above. The heat treatment of Nitronic 60 is one of the property metrics that distinguishes it from 304 / 316L.
Why does Nitronic 60 heat treatment matter?
For design engineering decisions, heat treatment directly affects component sizing, service envelope, and material substitution choices.
How is heat treatment 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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