Heat Treatment Specifications
Austenitizing
Temperature1177°C(2151°F)
Soak Time20 minutes
Tempering
Temperature551°C(1024°F)
Time120 minutes
Cycles2x
Quench Medium
plate
Target Hardness
64 - 66 HRC
Performance Characteristics
Toughness4/10
Edge Retention8/10
Corrosion Resistance2/10
Ease of Sharpening3/10
Overall Score17/40
Interesting Facts
- 1Crucible high-speed tool steel with high cobalt
- 2Equivalent to Hitachi HAP40 in properties
- 3Spyderco heat treats to incredible 66-67 HRC
- 4Prefers polished edge (unlike M4 which prefers toothy)
- 5Burnt orange handles are signature of Rex 45 sprint runs
Famous Uses
Spyderco Paramilitary 2 Sprint
Spyderco Native 5
Spyderco Manix 2
Spyderco Shaman
Best For
Folding knives
High-performance cutting
Superior edge retention
Similar Steels
M4 HSS
No cobalt
HAP72
Japanese competitor
Not Recommended For
- Wet environments (rusts)
- Budget
- Field sharpening
Expert Tips
- 1Excellent wear resistance from PM process
- 2High cobalt enhances red hardness
- 3Requires maintenance due to low corrosion resistance