Heat Treatment Specifications
Austenitizing
Temperature1050°C(1922°F)
Soak Time20 minutes
Tempering
Temperature540°C(1004°F)
Time120 minutes
Cycles3x
Quench Medium
air
Target Hardness
68 - 70 HRC
Performance Characteristics
Toughness2/10
Edge Retention10/10
Corrosion Resistance2/10
Ease of Sharpening1/10
Overall Score15/40
Interesting Facts
- 1Developed 1997 by Crucible as ultra-wear resistance HSS
- 2Can reach 70-72 HRC - beyond official Rockwell C scale max of 70
- 33.4% carbon, 9.5% vanadium, 10% tungsten, 9% cobalt
- 4Highest edge retention steel available, eclipses even Maxamet
- 5Extremely difficult to sharpen - 'killed ceramic belts on grinder'
- 6January 2025: Spyderco confirmed another production run coming
Famous Uses
Spyderco Sage 5
Custom extreme-edge knives
Best For
Maximum wear resistance
Specialized cutting
Industrial tools
Industrial cutting
Extreme wear environments
Maximum hardness applications
Similar Steels
Not Recommended For
- Any field sharpening
- Wet environments
- Common sense
Expert Tips
- 170-72 HRC achievable
- 2Extremely difficult to sharpen
- 3Coarse edges only
- 4PM technology
- 5HARDEST knife steel available (70-72 HRC)
- 6Professional sharpening recommended
- 7Coarse edge better than fine polish