HYS (Hayashi Powder Metal)
Description
HYS is Hayashi's proprietary powder metal steel at 63-64 HRC. Ultra-fine carbides deliver exceptional edge life for professional shears.
HYS (ハイス鋼)
Quick look
- Hardness window: 63–64 HRC after powder metallurgy processing and heat treatment.
- Toughness: Ultra-fine particle distribution (超微粒子) combined with molybdenum delivers exceptional 粘り (nebari / toughness-resilience) that prevents chipping at high hardness.
- Corrosion profile: Stainless-grade chromium content resists salon moisture and chemical staining with standard care.
- Weight/feel: PM density with balanced construction; firm, controlled closure.
Composition and metallurgy
HYS is Hayashi Scissors’ proprietary ultra-fine particle powder metal steel (超微粒子粉末鋼). The alloy leverages powder metallurgy technology (粉末冶金技術 / funmatsu yakin gijutsu) to achieve a carbide distribution that conventional casting cannot match. The key alloying elements each serve a specific purpose: tungsten provides hardness and wear resistance at the cutting edge, molybdenum adds toughness and the characteristic 粘り (nebari) that keeps the edge resilient under repeated stress, and vanadium refines the carbide grain structure for a smooth, consistent apex.
Why it matters
The core advantage of HYS over conventional steels like SUS440C lies in particle uniformity. Where SUS-series steels struggle with uneven carbide distribution—large particles next to small ones creating weak points along the edge—HYS achieves uniform particle size throughout the matrix. This consistency means the edge wears evenly and predictably rather than developing random chips or rough spots. Hayashi states that maintenance frequency with HYS is “incomparably lower” (比較にならないほど低い) than with conventional stainless steels, a claim supported by the 63–64 HRC hardness range that resists deformation through thousands of cuts.
Shear pairing & edge compatibility
- Hayashi convex precision shears: HYS is the backbone of Hayashi’s professional lines, paired with convex edges ground to exploit the steel’s fine grain.
- PM-grade thinning and texturizing tools: The uniform carbide structure keeps thin tooth profiles crisp over extended use.
Technique map
- Dry precision cutting where sustained edge sharpness across a full day of clients is non-negotiable.
- Slide and point work that demands a glassy-smooth blade surface to prevent hair catching or pushing.
- High-volume salon use where reduced sharpening frequency directly translates to lower maintenance cost and less downtime.
Real-world stress tests
- Edge retention: HYS at 63–64 HRC significantly outlasts VG-10 and cobalt alloys. Expect 1,500+ salon cuts before service is needed—the “incomparably lower” maintenance claim is credible at this hardness level.
- Impact/drop resilience: The molybdenum-enhanced toughness protects against catastrophic chipping, but 63+ HRC still means tip damage from drops is a real risk. Store carefully.
- Weight & in-hand feel: PM steel has a planted, controlled feel with firm closure. Less “spring” than softer cobalt alloys, more precision feedback.
Maintenance notes
Despite the extended edge life, HYS still requires routine care: wipe after every client, dry thoroughly at end of day, oil pivots weekly. When sharpening is finally needed, use a technician experienced with powder metallurgy steels—standard ceramic wheels may not cut efficiently at this hardness. Diamond or CBN abrasives are recommended.
Industry snapshot
- Hayashi Scissors (林シザース): HYS is exclusive to Hayashi’s product lines, manufactured in Japan with full in-house control over the powder metallurgy process and heat treatment.
Trade-offs
- Proprietary to Hayashi—no third-party sourcing or cross-brand availability.
- Requires PM-capable sharpening; standard salon sharpeners may not have appropriate equipment.
- Higher cost than conventional stainless or cobalt-alloy shears, reflecting the PM process complexity.
- At 63–64 HRC, the steel is less forgiving of technique errors or accidental contact with hard objects.
Sources
Related: HYS-MAX67 • SG Powder High Metal • Scissor Maintenance