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Nitronic 60 Magnetic Permeability (Non-Magnetic, mu_r < 1.005)

Nitronic 60 magnetic permeability below 1.005 in annealed condition, UNS S21800
Nitronic 60 magnetic permeability below 1.005 in annealed condition

Nitronic 60 magnetic permeability in the solution-annealed condition is essentially non-magnetic. Relative permeability (mu_r) is typically below 1.005, well below the threshold considered magnetically detectable (mu_r > 1.05). Heavy cold work induces a small permeability rise but Nitronic 60 austenite is more stable than 304 against strain-induced martensitic transformation, so the rise is much smaller. Suitable for instrumentation, MRI fixtures, naval mine warfare, and other low-permeability 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.

Permeability Detail and Application Envelope

Solution-annealed mu_r typically 1.002 to 1.005. The slight residual is from microstructural inhomogeneity, not from strain-induced martensite.

Cold-worked HS condition: mu_r can rise to 1.02 to 1.05 depending on cold-reduction percentage and grain refinement. Still essentially non-magnetic for most engineering definitions.

Comparison: 304 cold-worked can reach mu_r 1.20 to 2.00 due to strain-induced martensite. 316L stays closer to 1.005 after cold work. Nitronic 60 sits between, much closer to 316L due to austenite-stabilization from nitrogen.

Test method: ASTM A342 standard for direct-current measurement, or specific gauss-meter inspection at customer specification. Mill test certificates report on request.

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:

PropertySolution AnnealedCold-Worked HS
Yield Strength (0.2% offset)380 MPa (55 ksi) min620 MPa (90 ksi) min
Tensile Strength655 MPa (95 ksi) min860 MPa (125 ksi) min
Elongation (in 4D)35% min15% min
Hardness95 HRB max (~210 HB)30 HRC max
Impact (Charpy V at -196 C)54 J min-
Density7.62 g/cc7.62 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 PairThreshold Galling Stress (ASTM G98)Relative
304 / 30435 to 70 MPa1x baseline
316L / 316L35 to 70 MPa1x baseline
Nitronic 50 / Nitronic 50175 to 275 MPa3-5x
Nitronic 60 / Nitronic 60350 to 500 MPa5-10x

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

Related Nitronic 60 Forms and Fasteners

Request a Quote

For Nitronic 60 stock with verified magnetic permeability 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 magnetic permeability?

See the values in the table above. The magnetic permeability of Nitronic 60 is one of the property metrics that distinguishes it from 304 / 316L.

Why does Nitronic 60 magnetic permeability matter?

For design engineering decisions, magnetic permeability directly affects component sizing, service envelope, and material substitution choices.

How is magnetic permeability 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.