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 Helicoil Thread Inserts - Anti-Galling Stainless Inserts
Nitronic 60 Helicoil thread inserts (UNS S21800) are the anti-galling specification for tapped-hole reinforcement and thread repair in austenitic stainless service. Conventional 304 / 316L Helicoil inserts gall during installation against 304 / 316L parent material under the cold-welding adhesion failure mode. Nitronic 60 inserts install dry without anti-seize and tolerate 50+ reuse cycles without scoring the tap-driver, the parent material, or the bolt that engages the rebuilt thread. The high-Mn-Si-N anti-galling chemistry raises the threshold galling stress per ASTM G98 by 5 to 10 times over 304 / 316L self-mated. TorqBolt stocks Nitronic 60 Helicoils in UNF, UNC, and metric series from #4-40 / M3 through 1-1/4 inch / M30, free-running and screw-locking patterns.
Per info@torqbolt.com or +91-22-66157017 for a sized stock quote and lead time. 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.
Why Nitronic 60 Helicoil Inserts vs 304 / 316L Inserts
Helicoil inserts are coiled wire-thread inserts installed into a slightly oversized tapped hole to provide a hardened thread surface for a standard machine bolt. The insert wire is driven into the tapped hole and seats with both ID and OD engaging threaded surfaces under sliding contact. THAT sliding contact is where conventional stainless Helicoils fail.
- 304 stainless Helicoil failure mode, the wire surface and the tapped-hole walls cold-weld at the contact spots during installation, scoring both surfaces. First installation may complete but the insert is stuck; removal damages the parent thread. Bolt engagement may be acceptable for one tightening cycle.
- 316L stainless Helicoil failure mode, identical to 304. The 2-3 percent molybdenum adds chloride pitting resistance but does NOT address the adhesive cold-welding mechanism. Same galling failure under installation contact stress.
- Nitronic 60 Helicoil performance, the high-Mn-Si-N chemistry builds a tenacious Cr-Si surface oxide that resists film breakdown under contact pressure. Manganese reduces stacking-fault energy to favor planar slip without exposing virgin austenite. Threshold galling stress 350-500 MPa self-mated (ASTM G98) versus 35-70 MPa for 304 / 316L. The result, Nitronic 60 inserts install dry, do not score the tapped-hole walls, and the insert wire surface does not roughen against the installation driver.
- Reuse cycles, 304 / 316L inserts typically tolerate 1-3 install-remove cycles before galling damage retires the assembly. Nitronic 60 inserts tolerate 50+ cycles, useful for tooling, jigs, and field-serviceable assemblies that require repeated disassembly.
Nitronic 60 Helicoil Insert Sizes Available
Thread series, lengths, and patterns stocked from inventory or quoted on a short lead time:
| Series | Size Range | Lengths (× nominal D) | Pattern |
|---|---|---|---|
| UNC inch | #4-40 through 1-1/4 inch | 1D, 1.5D, 2D, 2.5D, 3D | Free-running, screw-locking |
| UNF inch | #4-48 through 1-1/4 inch | 1D, 1.5D, 2D, 2.5D, 3D | Free-running, screw-locking |
| Metric coarse | M3 through M30 | 1D, 1.5D, 2D, 2.5D, 3D | Free-running, screw-locking |
| Metric fine | M5 through M30 | 1D, 1.5D, 2D, 2.5D, 3D | Free-running, screw-locking |
| NPT pipe thread | 1/16 NPT through 1-1/2 NPT | Per NPT series | Free-running |
Diamond-cross-section wire profile per Helicoil standard, which produces a triangular thread cross-section that distributes bolt-engagement load across the full length of the insert. Tang-and-notch installation drives standard across all sizes.
Free-Running vs Screw-Locking Helicoil Patterns
Two pattern variants stocked, picked by service:
- Free-running, smooth uniform thread coil. The bolt engages with no axial preload from the insert itself. Use where vibration is low or where a separate locking element (lock washer, jam nut, threadlocker) provides loosening resistance.
- Screw-locking, one or more coils are deformed inward to produce a controlled friction grip on the bolt threads. The bolt requires slightly higher installation torque and provides locking against vibration loosening without a separate locking element. Used in aerospace, vibration-prone machinery, and rotating-equipment hardware.
For maximum locking force specify the maximum-grip variant; for nominal locking specify the minimum-grip variant. Both are stocked in Nitronic 60 wire.
Nitronic 60 Helicoil Standards Compliance
Wire feedstock and finished inserts manufactured to the following standards bodies:
| Standard | Scope | Applicable to |
|---|---|---|
| ASTM A580 | Stainless wire (UNS S21800) | Helicoil wire feedstock |
| AMS 5847 | Aerospace wire (ER218 / UNS S21880 cast variant) | Aerospace-quality wire |
| MIL-I-8846 | Insert, screw-thread, helical coil | Military and aerospace specification |
| NASM 8846 | National Aerospace Standard for Helicoil inserts | Aerospace replacement for MIL-I-8846 |
| NACE MR0175 / ISO 15156-3 | Sour-service material qualification | Annealed temper inserts in subsea wellhead service |
Material certification per EN 10204 3.1 by default; EN 10204 3.2 dual-witnessed third-party inspection (Lloyds, TUV, DNV, BV) available on request for aerospace, nuclear, and oilfield-critical orders. NACE MR0175 sour-service certification statement available for oilfield purchase orders.
Helicoil Insert Installation in Nitronic 60
Installation sequence is identical to conventional Helicoil but the Nitronic 60 wire eliminates the dry-installation galling risk. Standard procedure:
- Step 1, drill, drill the tapped hole to the spec drill size for the insert thread plus insert wire thickness. STI (Screw Thread Insert) drill chart governs.
- Step 2, tap, tap with a STI tap to the spec STI thread form. STI taps cut a thread cross-section sized to accept the insert at correct OD engagement. Conventional taps will NOT work.
- Step 3, install, screw the insert onto the installation tool by engaging the tang-drive notch. Drive the insert into the tapped hole until the top coil sits 1/4 to 1/2 turn below the parent surface.
- Step 4, break the tang, the installation tang is designed to break off at the notch after installation. A tang-break tool drives the notch and snaps the tang. The completed insert has full thread engagement above and below the break point.
- Step 5, inspect, the bolt should engage the insert smoothly without burred starts. For aerospace and nuclear orders a thread plug gauge confirms the post-installation thread fit class (typically 3B internal, 3A external bolt).
Nitronic 60 Helicoil Insert Applications
Dominant industry envelopes for Nitronic 60 Helicoil inserts:
- Aerospace, airframe fastener tapping in aluminum parent material where Nitronic 60 anti-galling matters during repeat-disassembly maintenance cycles. NASM 8846 / MIL-I-8846 compliant.
- Marine and offshore, deck hardware tapping in aluminum or stainless parent, salt-spray cycling tolerant.
- Nuclear, reactor coolant pump bolting, valve trim tapping where galling causes shutdown.
- Food processing, FDA-acceptable austenitic in mixer paddles, conveyor flights, sanitary fittings.
- Oil and gas downhole, subsea wellhead, NACE MR0175 sour-service compliant tooling and jig holes.
- Mold and die shops, mold-half clamping bolts in aluminum tool plates where Helicoils provide a hardened tapped surface and Nitronic 60 prevents installation galling.
- Cryogenic, LNG hardware where austenite stability to -196 C matters.
- Repeat-service tooling and jigs, where the assembly is disassembled and reassembled many times during the life of the tool. 50+ cycle tolerance vs 1-3 for 304 / 316L.
Helicoil Insert Material Comparison
Common Helicoil insert materials and where Nitronic 60 fits:
| Material | Galling Resistance | Corrosion | Cost | Best Use |
|---|---|---|---|---|
| 304 stainless wire | Poor (galls under installation) | Good general | 1x | Low-cycle, low-vibration |
| 316 stainless wire | Poor (galls under installation) | Excellent in chloride | 1.2x | Marine corrosion priority |
| 17-4 PH stainless wire | Moderate (higher hardness) | Good | 2x | High-load, single-install |
| Nitronic 60 wire (UNS S21800) | Excellent (5-10x vs 304/316L) | Good general | 2x | Repeat-cycle, anti-galling priority |
| Inconel 718 wire | Excellent | Outstanding (nickel) | 8x | High-temperature aerospace |
| Phosphor bronze wire | Excellent | Moderate | 1.5x | Non-magnetic, soft parent |
For most industrial repeat-cycle service Nitronic 60 is the engineering compromise, providing the anti-galling benefit of nickel-superalloy inserts at a stainless price point. See galling resistance for the underlying ASTM G98 data and Nitronic 60 vs 316L for a full material comparison.
Related Nitronic 60 Forms and Fasteners
Buyers of Nitronic 60 Helicoil inserts typically also need matching anti-galling fasteners:
- Hex bolts and stud bolts per ASTM A193 B8R bolting spec.
- Hex nuts and heavy hex nuts per ASTM A194 Grade 8R nut spec.
- Socket head cap screws and cap screws for fastener-with-insert applications.
- Threaded rod cut-to-length for stud applications.
- Dowel pins and clevis pins for repeated-disassembly precision-fit service.
- Bushings for sliding-contact mating-shaft service.
- Nitronic 60 wire per ASTM A580 for custom-formed inserts and spring wire per AMS 5847.
- Full Nitronic 60 fastener portfolio.
Request a Quote
For Nitronic 60 Helicoil thread inserts in any size from #4-40 / M3 through 1-1/4 inch / M30, free-running or screw-locking, 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 a Helicoil thread insert?
A coiled-wire thread insert installed into a slightly oversized tapped hole, providing a hardened thread surface for a standard machine bolt. Used to repair stripped threads, reinforce tapped holes in soft parent materials (aluminum), or provide a permanent anti-galling thread surface in stainless parent material.
Why use Nitronic 60 Helicoil inserts instead of 304 or 316L?
304 and 316L Helicoils gall during installation against the tapped-hole walls. The cold-welding adhesion mechanism scores both surfaces. Nitronic 60 wire chemistry (high Mn-Si-N) eliminates this failure mode, allowing dry installation and 50+ reuse cycles versus 1-3 cycles for 304 / 316L.
What sizes are stocked?
UNC, UNF, and metric coarse / fine series from #4-40 / M3 through 1-1/4 inch / M30. Lengths 1D, 1.5D, 2D, 2.5D, and 3D. Free-running and screw-locking patterns. Custom NPT pipe-thread inserts on a short lead time.
Are Nitronic 60 Helicoils NACE MR0175 compliant?
Yes, in the solution-annealed condition (95 HRB max hardness). Cold-worked-temper inserts may exceed the hardness limit and require end-user spec endorsement. See NACE MR0175.
Can Nitronic 60 Helicoils be reused?
Yes. The anti-galling chemistry tolerates 50+ install-remove cycles without scoring the insert wire surface or the tapped-hole walls. 304 / 316L Helicoils typically tolerate 1-3 cycles.
What is the difference between free-running and screw-locking Helicoils?
Free-running has uniform thread coils with no locking grip on the bolt. Screw-locking has one or more deformed coils that grip the bolt under controlled friction, providing vibration-loosening resistance. Both are stocked in Nitronic 60 wire.
Do I need anti-seize compound?
No. Nitronic 60 wire installs dry. Anti-seize introduces torque-scatter, contaminates the assembly, and may degrade in service. The dry-installation property is one of the key reasons buyers specify Nitronic 60 over 304 / 316L Helicoils.
What is the installation tool?
Standard tang-drive Helicoil installation tool for the matching thread series. After installation a tang-break tool snaps off the installation tang at the breakoff notch. No special Nitronic-60-specific tooling required.
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