LY-601 Polyimide (PI) for Ultra-High-Temperature Wear Applications
When an application must run continuously at temperatures above what most engineering plastics can survive, and wear must stay low, polyimide (PI) is often the only answer. LY-601 is a high-performance polyimide grade engineered for exactly this envelope — measured for continuous operation around 360 °C, with a glass-transition temperature of ~290 °C and excellent wear resistance. This guide explains what LY-601 does, the verified data behind it, and the bearing, sealing, and semiconductor applications where it earns its place.
1. What Is LY-601?
LY-601 is an aromatic polyimide (PI) compound. Polyimides are a family of ultra-high-performance polymers known for:
- No true melting point — they withstand extreme continuous temperatures where thermoplastics soften
- Excellent thermal, radiation, and vacuum outgassing performance
- Low wear and friction in dry, high-temperature sliding
- High compressive strength and dimensional stability
Unlike PEEK, PI does not melt cleanly and is typically produced by compression moulding, sintering, or hot-pressing, followed by machining — which is why PI parts are often near-net-shape plus precision CNC finishing.
2. LY-601 Verified Performance Data
The following values are measured on LY-601 PI (ISO methods, from Dalian Luyang's material properties table):
| Property | LY-601 value | Test method |
|---|---|---|
| --- | --- | --- |
| Continuous operating temperature | ~360 °C | UL 746B |
| Glass-transition temperature (Tg) | 290 °C | ISO 11357 |
| Heat deflection temperature (HDT, 1.8 MPa) | 287 °C | ISO 75 |
| Density | ~1.27 g/cm³ | ISO 1183 |
| Tensile strength, 23 °C | 56 MPa | ISO 527 |
| Tensile strength, 200 °C | ~42 MPa | ISO 527 |
| Flexural strength, 23 °C | ~88 MPa | ISO 178 |
| Compressive strength, 23 °C | ~143 MPa | ISO 604 |
| Coefficient of friction, 23 °C | ~0.28 | GB/T 3960 |
| Wear volume, 23 °C | 0.75 ×10⁻³ cm³ | — |
The distinctive pair of numbers is the continuous operating temperature of ~360 °C (far above PEEK's ~260 °C) combined with a very low wear volume of 0.75 ×10⁻³ cm³ — meaning LY-601 keeps sliding surfaces alive in environments where PEEK or PTFE-based parts would either soften or wear away.
3. Thermal Envelope: What ~360 °C Continuous Means in Practice
LY-601's combination of a 360 °C continuous rating, Tg ~290 °C, and HDT ~287 °C (1.8 MPa) means it retains useful mechanical load capacity into the range where most thermoplastics have effectively stopped working. Two caveats worth stating:
- Continuous-use rating assumes a defined (often low) mechanical load. A loaded wear part at 360 °C will see more stress than an unloaded spacer. Always validate against your operating stress, not just the temperature number.
- Dry service is preferred. Like all polyimides, LY-601 has limited resistance to hydrolysis — it should be avoided in prolonged hot water or steam service, where a hydrolytically stable material like PEEK is the better choice.
4. LY-601 vs PEEK at High Temperature
PEEK is the everyday high-temperature workhorse (to ~260 °C); LY-601 extends the envelope upward:
| Property | PEEK (e.g., LY-100 series) | LY-601 PI |
|---|---|---|
| --- | --- | --- |
| Continuous operating temp | ~260 °C | ~360 °C |
| Tg | ~143 °C | ~290 °C |
| HDT (1.8 MPa) | ~155 °C | ~287 °C |
| Processability | Injection/extrusion/CNC | Compression/sintering + CNC |
| Hydrolysis resistance | Good | Poor — avoid wet steam service |
| Relative cost | Moderate | High |
Rule of thumb: use PEEK below ~260 °C where processability, toughness, and water resistance win; reach for LY-601 PI when the service temperature climbs beyond PEEK's comfortable continuous range and the environment is dry.
5. Applications That Justify PI
LY-601 earns its cost where nothing else survives:
Bearings and sliding components
High-temperature bearings, bushings, thrust washers, and seal faces where PEEK or PTFE-based parts would soften, creep, or wear — LY-601's low wear volume (0.75 ×10⁻³ cm³) and retained strength at 200 °C (42 MPa) keep them running.
High-temperature seals and valve internals
Seal seats, back-up rings, and valve components in dry, hot gas/oil service where standard elastomers and many plastics fail.
Semiconductor processing
Wafer carriers, test sockets, and fixtures in ion-implantation, deposition, and etch chambers where temperature, vacuum, and low outgassing are requirements — PI's low-outgassing, radiation tolerance, and 360 °C rating fit the chamber environment.
Aerospace and spacecraft
Bushings, brackets, and radiation-resistant components where PI's combination of extreme temperature, vacuum outgassing, and radiation resistance is unmatched.
6. How LY-601 Parts Are Made
Because PI does not readily melt, LY-601 parts are typically:
- Compression-moulded or hot-pressed to near-net shape
- Sintered / consolidated (in some cases with post-imidisation)
- CNC machined to final precision tolerances
This near-net-shape-plus-machining route drives the higher cost of PI parts and sets expectations on geometry and volume. For a precision bearing or seal, the process delivers exceptional dimensional accuracy and consistency.
7. Specification Checklist for LY-601 / PI Parts
- [ ] Confirm continuous operating temperature rating for your actual operating load
- [ ] Confirm dry service (avoid hydrolysis in steam/hot water)
- [ ] Datasheet with ISO/ASTM test methods; grade and lot traceability
- [ ] Wear/friction data for your speed, load, and temperature
- [ ] Dimensional inspection report (tolerance, flatness, concentricity)
- [ ] ISO 9001 quality system; ISO 13485 where applicable
- [ ] Prototype/machining capability to validate geometry before quantity
Frequently Asked Questions
- What is the continuous operating temperature of LY-601 PI? Approximately 360 °C, with a glass-transition temperature of ~290 °C and heat deflection temperature ~287 °C at 1.8 MPa (measured per UL 746B / ISO standards).
- Is LY-601 suitable for steam or wet service? No — like all polyimides it has limited hydrolysis resistance and should be used in dry service. For hot wet/steam applications, a hydrolytically stable material such as PEEK is the better choice.
- How is LY-601 PI processed? It does not melt cleanly; parts are compression-moulded/sintered (often hot-pressed) to near-net shape and then CNC machined to final tolerance.
Related Topics
- Polyimide (PI) vs PEEK: Selecting High-Temperature Engineering Plastic
- PEEK vs PTFE vs Polyimide for Sealing: Which Material, When?
- PEEK Properties: A Complete Engineering Guide
Dalian Luyang Technology Development Co., Ltd. (www.newmaterialchina.com) manufactures PEEK, PI, and PTFE precision parts — seals, inserts, machined components, and electrolyser frames — under ISO 9001 and ISO 13485. Established 2006. Contact: liyulong@luyangkeji.com · WhatsApp +86 15989781752. This guide is educational reference material; always verify against your chosen grade's official datasheet.