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 Round Bar (ASTM A276 / A479)
Nitronic 60 round bar (UNS S21800) is the workhorse stock form for anti-galling fasteners, valve stems, pump shafts, and machined Helicoil-class thread inserts. Supplied solution-annealed at 1010-1120 C with water quench, hardness 95 HRB max, yield 380 MPa min and tensile 690 MPa min in the annealed condition. TorqBolt cuts to length and supplies with EN 10204 3.1 / 3.2 MTC documentation traceable to mill source.
ASTM A276 vs A479, Which Spec
ASTM A276 covers stainless steel bars and shapes for general industrial service and is the primary product spec for Nitronic 60 round bar. ASTM A479 covers bars and shapes for use in boilers and other pressure parts with stricter testing and certification requirements. Order to A479 when the bar will be machined into pressure-containing components (valve bodies, pump shafts inside pressure boundaries) or where ASME B&PV code traceability is required. Order to A276 for fasteners, structural components, and non-pressure machined parts. Both specs reference the same UNS S21800 chemistry and same annealed mechanical-property minimums.
Size Range & Tolerances
| Diameter Range | Length Range | Surface Finish |
|---|---|---|
| 1/4 inch (6.35 mm) to 12 inch (305 mm) | up to 6.1 m (20 ft) standard; longer on request | hot-finished black, hot-finished pickled, cold-drawn, centerless ground, peeled / turned, polished |
Diameter tolerances per ASTM A484 for hot-finished bar; cold-drawn and ground bar held to tighter tolerances per A484 Class 3 or to customer-specified limits. Straightness 1/16 inch per 5 ft maximum on cold-finished bar.
Mechanical Properties (Annealed)
| Property | ASTM A276 / A479 Min | Typical |
|---|---|---|
| Tensile strength | 690 MPa (95 ksi) | 760 MPa (110 ksi) |
| Yield strength 0.2% | 380 MPa (55 ksi) | 430 MPa (62 ksi) |
| Elongation in 50 mm | 35% min | 50% |
| Reduction of area | 55% min | 65% |
| Hardness, annealed | 95 HRB max | 87-92 HRB |
Cold-Worked HS Condition
Cold-drawn or strain-hardened Nitronic 60 round bar reaches yield ~830 MPa (120 ksi) with elongation around 15-20%. Hardness rises into the HRC range. The cold-worked condition exits the NACE MR0175 / ISO 15156-3 sour-service hardness window, so specify annealed bar for sour-service downstream parts unless the end-user spec explicitly accepts cold-worked. See yield strength for full annealed-vs-cold-worked data.
Common Applications
- Anti-galling fasteners (hex bolts, stud bolts, nuts, threaded rod, helicoil inserts)
- API 6A subsea valve stems and gate-valve trim
- Pump shafts and slurry-handling rotor stock
- Screw conveyor shafts for food-processing and chemical service
- Marine deck hardware machined bar stock
Heat Treatment Condition
Standard supply is solution-annealed at 1010-1120 C (1850-2050 F) followed by water quench. This dissolves carbides and nitrides into the austenite, locking the high-Mn-Si-N solid-solution chemistry in place. There is no aging step; Nitronic 60 is not precipitation-hardenable. After heavy machining, parts may be re-solution-annealed to restore the annealed property profile if cold work has shifted hardness above 95 HRB. See heat treatment for full cycle and quench-rate guidance.
Cut-to-Length & Machining Service
TorqBolt supplies bar cut to length with bandsaw or abrasive-disc cutoff to within +/-0.5 mm on length. Pre-machined bar (centerless ground, peeled, turned to OD tolerance) is available on request. CNC lathe and 5-axis mill capacity for finished components is in-house, with EN 10204 3.1 or 3.2 MTC issued at final inspection.
Request a Quote
For Nitronic 60 round bar in any size with cut-to-length and EN 10204 MTC documentation, 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 3.1 / 3.2 MTC documentation samples.
Frequently Asked Questions
Should I order to ASTM A276 or A479?
A276 for general industrial use, structural, fasteners, machined non-pressure parts. A479 for bars going into pressure-containing components (valves, pumps inside pressure boundary) or where ASME B&PV code traceability is required.
What sizes are stocked?
1/4 inch (6.35 mm) through 12 inch (305 mm) diameter, lengths up to 6.1 m (20 ft) standard. Larger diameters and longer lengths on quoted basis.
Is the bar magnetic?
Annealed Nitronic 60 round bar is essentially non-magnetic (relative permeability typically below 1.005). Heavy cold work induces small permeability rises, still well below ferritic or martensitic stainless levels.
Can I order to NACE MR0175 in cold-worked condition?
Cold-worked Nitronic 60 typically exceeds the 95 HRB NACE MR0175 hardness limit. For sour service order solution-annealed bar; cold-worked acceptance requires explicit end-user spec endorsement.
What MTC is included?
EN 10204 Type 3.1 standard (manufacturer cert with mechanical and chemical results). Type 3.2 (third-party endorsement) on request, required for API 6A and most NACE-critical service.
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