Walter Tiger-tec Grade Family Overview
Walter AG’s Tiger-tec coating technology is one of the most recognized PVD coating platforms in CNC turning. The Tiger-tec family includes three main variants — Gold, Silver, and Bronze — each engineered for specific application ranges within steel, stainless steel, and cast iron machining. Understanding the differences between these grades is essential for optimizing tool life, cutting speed, and surface quality in your turning operations.
Tiger-tec Coating Technology
All Tiger-tec grades use Walter’s proprietary HiPIMS (High Power Impulse Magnetron Sputtering) PVD process, which produces an extremely smooth, dense coating with superior adhesion to the carbide substrate. The HiPIMS process creates coating layers that are 30-50% smoother than conventional PVD coatings, reducing friction at the chip-tool interface and preventing built-up edge formation.
Tiger-tec Gold (WMP20S / WSM20)
Tiger-tec Gold is the premium grade in the family, combining a hard AlTiN-based coating with a gold-colored TiAlN outer layer. It is designed for high-speed finishing and medium turning of steel and stainless steel.
Key specifications:
- ISO classification: P10-P25, M10-M25
- Coating: HiPIMS AlTiN + TiAlN (3-4 um)
- Substrate: Fine-grain WC-Co (6-7% cobalt)
- Hardness: 3200 HV (coating surface)
- Recommended speed range: Vc = 180-380 m/min (steel), 80-200 m/min (stainless)
Tiger-tec Silver (WMP25S / WSM30)
Tiger-tec Silver uses a balanced AlCrN-based coating that offers a good compromise between wear resistance and toughness. The silver-gray color comes from the CrN component. This is the most versatile grade in the lineup.
Key specifications:
- ISO classification: P15-P35, M15-M30, K15-K30
- Coating: HiPIMS AlCrN (3-5 um)
- Substrate: Medium-grain WC-Co (8% cobalt)
- Hardness: 2800 HV (coating surface)
- Recommended speed range: Vc = 140-300 m/min (steel), 60-160 m/min (stainless)
Tiger-tec Bronze (WMP35 / WSM40)
Tiger-tec Bronze features a thicker, multi-layer TiAlN coating with a bronze-colored appearance. It prioritizes edge toughness and thermal shock resistance for interrupted cutting and heavy roughing.
Key specifications:
- ISO classification: P25-P45, M25-M40, K20-K40
- Coating: Multi-layer TiAlN (5-7 um)
- Substrate: Coarse-grain WC-Co (10% cobalt)
- Hardness: 2500 HV (coating surface)
- Recommended speed range: Vc = 100-220 m/min (steel), 50-120 m/min (stainless)
Comprehensive Grade Comparison Table
| Property | Gold (WMP20S) | Silver (WMP25S) | Bronze (WMP35) |
|---|---|---|---|
| ISO range (steel) | P10-P25 | P15-P35 | P25-P45 |
| ISO range (stainless) | M10-M25 | M15-M30 | M25-M40 |
| Coating type | AlTiN + TiAlN | AlCrN | TiAlN multi-layer |
| Coating thickness | 3-4 um | 3-5 um | 5-7 um |
| Coating hardness | 3200 HV | 2800 HV | 2500 HV |
| Substrate toughness | Moderate | Good | Excellent |
| Max speed (steel) | 380 m/min | 300 m/min | 220 m/min |
| Interrupted cut rating | Fair | Good | Excellent |
| Surface finish capability | Ra 0.4-1.2 um | Ra 0.8-2.0 um | Ra 1.6-3.2 um |
| Wet cutting suitability | Excellent | Good | Fair (prefer dry/MQL) |
| Cost per insert | Premium | Mid-range | Economy |
Cutting Parameters for Steel Turning (AISI 4140, 280 HB)
| Grade | Operation | Vc (m/min) | fn (mm/rev) | ap (mm) | Expected Tool Life |
|---|---|---|---|---|---|
| Gold (WMP20S) | Finishing | 280-350 | 0.10-0.20 | 0.3-1.5 | 50-70 min |
| Gold (WMP20S) | Medium | 220-280 | 0.20-0.35 | 1.5-3.0 | 35-50 min |
| Silver (WMP25S) | Medium | 180-250 | 0.25-0.40 | 2.0-4.0 | 35-55 min |
| Silver (WMP25S) | Roughing | 150-200 | 0.35-0.55 | 3.0-5.0 | 30-45 min |
| Bronze (WMP35) | Roughing | 120-180 | 0.40-0.65 | 3.5-7.0 | 25-40 min |
| Bronze (WMP35) | Heavy interrupted | 100-150 | 0.30-0.50 | 2.5-5.0 | 20-35 min |
Application-Specific Recommendations
Automotive shaft turning (AISI 1045, continuous, high volume): Tiger-tec Gold at Vc=320 m/min delivers the best combination of tool life (60+ minutes) and surface finish (Ra 0.8 um). The smooth HiPIMS coating prevents BUE even at low feed rates.
Hydraulic valve body turning (AISI 316L stainless, interrupted): Tiger-tec Silver provides the best balance. At Vc=120 m/min, fn=0.25 mm/rev, it achieves 40 minutes tool life with good chip control. Gold would chip at the interruptions; Bronze would build up material on the cutting edge.
Heavy equipment pinion turning (AISI 4340, forged, scaled): Tiger-tec Bronze at Vc=130 m/min handles the forge scale and interrupted surfaces without chipping. Tool life averages 30 minutes, which is acceptable given the severe conditions.
Coolant Strategy for Each Grade
The coating type influences the optimal coolant approach:
| Grade | Coolant Recommendation | Rationale |
|---|---|---|
| Gold | Flood coolant or high-pressure (70+ bar) | AlTiN coating benefits from thermal stability provided by coolant |
| Silver | Flood or MQL (minimum quantity lubrication) | AlCrN coating performs well in both wet and semi-dry conditions |
| Bronze | Dry or MQL preferred | Thick TiAlN coating insulates substrate; flood coolant can cause thermal shock |
Conclusion
Walter’s Tiger-tec Gold, Silver, and Bronze grades cover the full spectrum of turning applications. Gold excels in high-speed finishing and precision work, Silver provides versatile performance across medium and roughing operations, and Bronze delivers maximum toughness for heavy and interrupted cuts. By matching the grade to your specific material, cutting conditions, and production requirements, you can optimize both tool life and part quality while minimizing cost per component.
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