Wire thread insert
0102030405
FH‑Flight 321 Stainless Steel Wire Thread Inserts | Titanium‑Stabilized High‑Temp Thread Reinforcement
1. Product Introduction
FH‑Flight 321 stainless‑steel wire thread inserts are helical thread reinforcement coils manufactured from AISI 321 titanium‑stabilized austenitic stainless steel (EN 1.4541 / UNS S32100). Compared with common 304 stainless steel, titanium element is added to bind carbon atoms and restrain chromium‑carbide precipitation at 450‑850 ℃ thermal cycling environment, effectively preventing intergranular corrosion failure.
Available in Free‑Running (FR) and Screw‑Lock (SL) anti‑loose types, both standard tang‑type and tailless versions are optional. After installation into ST tapped holes, they form ISO‑standard internal threads to strengthen low‑strength base materials such as aluminum alloy, cast iron, and repair stripped threads under high‑temperature working conditions. Products comply with DIN 8140 and GJB 119 aerospace specifications.
2. Core Unique Advantages of 321 Material
✅ Anti‑intergranular corrosion: Titanium‑stabilized alloy avoids grain‑boundary corrosion after long‑time high‑temperature thermal cycling, solving the main failure pain point of ordinary 304 inserts under medium‑high temperature.
✅ Excellent high‑temperature creep resistance: Maintains stable mechanical property under continuous working temperature up to 550 ℃, short‑term peak temperature reaches 600 ℃.
✅ Good oxidation resistance: Resists surface oxidation under long‑term heating service for thermal equipment.
✅ Retain original wire‑insert merits: Even stress distribution, improve fatigue life of threaded joints; both anti‑vibration free‑running and Screw‑lock locking versions are available.
✅ Weld‑compatible: Adapts for components subjected to welding or post‑weld heating, no extra solution treatment required.
✅ Multiple styles: Support tang‑type / tailless, metric / imperial thread specifications.
3. Material Performance Comparison: 321 VS 304 VS 316
| Item | FH‑Flight 321 (1.4541) | 304 (1.4301) | 316 (1.4401) |
|---|---|---|---|
| Key alloying element | Titanium‑stabilized | Standard Cr‑Ni | Molybdenum‑added |
| Long‑term service temperature | Up to 550 ℃ | Up to 315 ℃ | Up to 300 ℃ |
| Intergranular‑corrosion resistance under thermal cycling | Excellent | Poor (prone to sensitization) | Fair |
| Medium‑high‑temperature creep performance | Good | General | General |
| Chloride‑ion corrosion resistance | Moderate | Moderate | Excellent |
| Typical working scenario | Thermal cycling, high‑temperature equipment | Normal‑temperature general machinery | Marine / chemical corrosive environment |
Note: 321 material is not recommended for chloride‑rich marine environment; please choose 316 stainless‑steel inserts for such conditions.
4. Product Series & Application Scenarios
FR‑321 Free‑Running Wire Inserts
Smooth non‑locking coils, low thread friction, suitable for repeated assembly‑disassembly under high‑temperature thermal cycling conditions.
Application: Heat‑exchanger equipment, boiler auxiliary parts, high‑temperature test fixtures.
SL‑321 Screw‑Lock Anti‑Vibration Wire Inserts
Built‑in polygonal locking coil, provides elastic friction locking force to stop bolt loosening under combined high‑temperature + vibration load.
Application: Engine exhaust assemblies, turbo‑charger housings, aerospace high‑temperature light‑alloy threaded joints.
Available structure: conventional tang‑type wire insert; optional tailless 321 insert for blind‑hole assemblies.
5. Specifications & Surface Treatment
- Thread standard: Metric ISO M2‑M30; Imperial UNC / UNF.
- Insert length: 1d / 1.5d / 2d / 2.5d / 3d.
- Thread tolerance: Internal thread ISO 6H standard; aviation customized 5‑H high precision.
- Surface options: Natural bright finish, dry‑film solid lubricant, silver plating.
6. Installation Instructions
- Drill pilot hole according to the size table.
- Tap with FH‑Flight special ST tap.
- Mount insert by standard wire‑thread‑insert installation mandrel. For tailless variant, adopt dedicated tailless mounting tool.
- For tang‑type inserts, break off tang after installation for through‑hole parts; tang retention is allowed for blind‑hole conditions.
- Installation tools support manual torque wrench, electric and pneumatic assembly guns for batch production.
7. Main Application Industries
- Aerospace: High‑temperature light‑alloy structural threaded connections, auxiliary engine components.
- Power & Thermal Equipment: Heat exchangers, boiler accessories, high‑temperature test stands.
- Automotive & Heavy‑Duty Machinery: Exhaust housings, turbo‑charger parts, high‑temperature vibration components.
- Petrochemical Industry: Medium‑temperature process equipment, thermal‑cycling valve bodies.
- General high‑temperature equipment: Furnace‑body assemblies, heating‑device threaded reinforcement and thread repair.
8. Manufacturer Introduction
Xinxiang Flight Fasteners Co., Ltd, brand FH‑Flight, with over 20‑year experience in threaded‑insert manufacturing. We are capable of precision forming for special alloy including 321 titanium‑stabilized stainless steel. Passed ISO 9001 and GJB 9001 military‑quality‑system certification.
We supply standard stock items and accept custom orders for special length / special surface treatment 321 wire‑thread inserts for high‑temperature industrial customers around the globe.
