440C vs AUS-8: Material Data and Scissor Model Evidence
What's the difference between 440C and AUS-8 scissor steel?
440C and AUS-8 are stainless blade-material designations with different published chemistry. Carpenter’s 440C document and Fukaumi’s AUS-8 plate table describe their own material conditions. Neither grade name determines whether a finished scissor is a starter, backup or advanced tool.
Compare the source of each number before comparing products. Fukaumi’s AUS-8 processing reference and Kanetsune’s WS-38 thinning-model specification have different scopes. Utsumi’s AUS-8 NOVA Slim L is a beveled grooming model; its length and alloy do not establish a salon cutting role.
Updated Sep 2026 · 4 sources
| Attribute | 440C Stainless Steel Multiple producers; verify supplied material origin | AUS-8 Stainless Steel Japan | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Material hardness | ≈60 HRC; Carpenter Technology; heat-treated CarTech 440C under the producer datasheet conditions. Mill source | 59.0 HRC; Aichi Techno Metal Fukaumi; published quench-and-temper reference for AUS-8 material; not a finished-scissor value. Maker material source | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Finished-scissor examples | No model figure cited. | 58–59 HRC; Kanetsune USA WS-38 thinning scissors; maker-stated finished-scissor hardness. Model source | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Published composition | Carpenter CarTech 440C (UNS S44004). Producer type analysis, edition 1 June 1987, still hosted by Carpenter. Preserve printed ranges and maxima; the document disclaimer describes typical or average data, not a shipment guarantee. Composition source
Elements absent from this table are unreported in this source, not zero. These material figures do not identify the chemistry of an individual finished scissor. Indicative PREN: unavailable. No calculation: Mo, N lacks a published point value or two-sided range. Missing values and one-sided limits are not zero. Calculation and limits. | Aichi Techno Metal Fukaumi AUS-8 plate. Published Aichi Techno Metal Fukaumi rolled-plate composition ranges and maximum limits. Not a lot analysis; unreported nitrogen is unknown. Composition source
Elements absent from this table are unreported in this source, not zero. These material figures do not identify the chemistry of an individual finished scissor. Indicative PREN: unavailable. No calculation: N lacks a published point value or two-sided range. Missing values and one-sided limits are not zero. Calculation and limits. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Steel family | Martensitic stainless | Martensitic stainless | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Product links | Full entry | Full entry |
Comparing documented materials and models
Carpenter’s CarTech 440C datasheet gives carbon at 0.95–1.20% and chromium at 16.00–18.00%. Fukaumi’s AUS-8 plate table gives carbon at 0.70–0.80% and chromium at 13.0–14.5%. These are source-specific composition ranges. They do not form a universal price, corrosion or service-life ranking.
The shared evidence tables retain ranges, maximum limits and missing information separately. In particular, absent nitrogen must remain unknown rather than being treated as zero for a PREN calculation. Each source’s product form and processing context matter when deciding whether two numbers are comparable.
What the hardness statements actually describe
| Published statement | Evidence scope |
|---|---|
| Carpenter: about 60 HRC | Heat-treated CarTech 440C under the datasheet’s conditions |
| Fukaumi: 59.0 HRC | AUS-8 material processing reference |
| Kanetsune USA WS-38: 58–59 HRC | Named hair-thinning model specification |
| Utsumi America NOVA Slim L | No numeric hardness in the reviewed model listing |
The Carpenter sheet has an edition date of 1 June 1987 and describes its data as typical or average, not a shipment guarantee. Keep that qualification with its figures. The two AUS-8 hardness statements also remain attached to their respective material and model sources; neither certifies NOVA Slim L.
Why the finished application matters
Kanetsune’s WS-38 is a documented hair-thinning model. NOVA Slim L is listed for grooming with a beveled edge and flat blade. A shared AUS-8 label therefore cannot prescribe a convex salon edge or a long-hair technique.
The retained photographs identify catalog examples. They do not demonstrate alloy chemistry or finished hardness. The 440C reference and AUS-8 reference provide the full material context; the NOVA Slim L record retains its named product evidence.
From a grade comparison to a model decision
Use the material table to identify which claim belongs to which document. Then compare the exact finished tools: intended use, handedness, actual dimensions, edge form, adjustment, care instructions, service route and full purchase quote. A grade name does not establish comfort, control, edge life, price tier or a sharpening interval.
If two sellers quote hardness, retain the model, blade component, scale and source with each figure. A statement about quenched steel stock and a specification for assembled scissors answer different questions. Where a field is absent, ask for evidence instead of borrowing a number from a neighboring grade or another model.
For a practical comparison, record the same task and conditions for each pair and distinguish your observation from a material-wide claim. A result with one tool is useful for that decision; it does not establish how every product with the same alloy label will behave.
Sources
- Carpenter Technology: CarTech 440C Stainless datasheet (manufacturer datasheet)
- 🇯🇵 Aichi Techno Metal Fukaumi: High-strength stainless plate (material supplier)
- Kanetsune USA: WS-38 AUS-8 thinning scissors (regional product listing)
- Utsumi America: NOVA Slim L 75/85 grooming shears (regional product listing)