Cobalt-alloy steels are a hallmark of Japanese convex shears, prized for their buttery closing action and corrosion resistance. Understanding how cobalt changes edge behavior helps you justify upgrades and tailor maintenance schedules.
Why Add Cobalt?
- Softer feel at high polish: Cobalt reduces friction and allows convex blades to glide silently.1
- Heat resistance: Edges stay stable during polishing and sharpening, preserving ride lines.
- Corrosion protection: Cobalt and molybdenum improve resistance to salon chemicals and humidity.
Common Cobalt Blends
- ATS-314: Popular in Yasaka; balances cobalt with carbon for durability.
- VG-10: Used in Kasho/Joewell premium lines; hardened to 60–62 HRC for longevity.
- Proprietary blends: Hikari and Mizutani tailor cobalt content to series-specific cutting feel.
Impact on Maintenance
- Requires convex-specialist sharpening with water-cooled wheels.
- Wipe and oil after every client; corrosion resistance is high but not absolute.
- Monitor tension closely—cobalt blades can chip if forced closed on dry hair or thick sections.
Who Benefits Most
- Precision stylists performing dry finishes and point work.
- Salon owners wanting premium experience for signature services.
- Stylists ready to invest in regular factory refurbishment.
Related Reading
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Steel and hardness overview in
docs/TERMINOLOGY.md. ↩