SUS440C Steel

Reference sectionSUS440C Steel

Quick look

• Designation: SUS440C appears alongside 440C in a primary industry comparison, with an explicit equivalence limitation.
• Composition: The selected material record uses a supplier table specifically labeled SUS440C.
• Hardness: A processing reference is separate from a finished-scissor specification.
• Documented models: Yasaka publishes SUS440C for both SA-5.5 and SA-5.5 OF, with different blade lengths.

Why it matters

Japan Stainless Steel Association lists SUS440C, AISI 440C and UNS S44004 in the same comparison row. Its warning matters: correspondence does not guarantee interchangeability, and specifications can differ in composition, properties and tests. The table covers several product forms, so citing “JIS” alone does not identify the complete purchasing specification. JSSA comparison and limitation.

Use the 440C reference to compare the separately sourced designation. Keep the name on the original maker document when describing a product. This page does not substitute a generic 440C chemistry table for SUS440C, and a Japanese designation does not itself establish where a finished scissor was made.

Supplier composition and hardness

Aichi Techno Metal Fukaumi publishes SUS440C plate values: carbon 0.95–1.20%, chromium 16.00–18.00%, and maxima of 0.8% silicon, 1.0% manganese, 0.04% phosphorus, 0.005% sulfur, 0.30% nickel and 0.75% molybdenum. The structured table preserves those ranges and limits. Vanadium is a dash; nitrogen is unlisted. Neither is recorded as zero. Named SUS440C plate row.

This is a supplier’s published product record, not a reproduced full JIS standard or an analysis certificate for a purchased pair. For procurement, ask which material specification and revision apply and whether the offered documentation concerns the actual batch.

The same supplier gives 60.0 HRC as a quench-and-temper reference. Its separate mechanical-properties table reports 254 HV20 for SUS440C. These entries have different contexts and scales; neither is assigned to every finished scissor. No scale conversion or complete heat-treatment recipe is inferred here. Material tables.

Pairing contextShear pairing & edge compatibility

A maker’s material field identifies one part of the product. It does not establish whether the edge is convex, beveled, micro-serrated or suitable for a specific service technique. Retain those as separate questions when comparing a listing with the pair you will receive.

A photograph can help identify branding, handle form and visible fittings. It cannot establish chemical analysis, test hardness or reveal all the blade contact geometry. The retained Mina Umi image is a catalog illustration; the verified manufacturer examples below provide a clearer basis for the named-grade discussion.

Process routeTechnique map

Begin with the task and the model’s stated intended use. A shared steel designation cannot decide blade reach for over-comb work, tip access for detailing or suitability for sliding. In particular, neither a higher carbon figure nor a chromium range proves that a finished blade has greater stiffness or a particular feel through hair.

When assessing a pair, record the task, section, blade position and adjustment. Keep observations specific: a pair that pushes hair at one point needs investigation of its condition and setup. Calling that result a universal SUS440C trait loses the information needed to resolve the problem.

Claims to evaluatePerformance evidence

No independent salon trial or scissor drop test is presented in the reviewed material and product records. They do not establish that a SUS440C tip normally rolls instead of chipping, that a technician can always restore it with minimal blade loss, or that its cutting feel ranks below VG-10 or ATS-314.

For a claim of longer edge life, ask what was compared, how the tools were used and what counted as the end of useful cutting. A hardness number alone supplies none of those details. Similarly, stainless classification and chromium content are insufficient evidence for approving exposure to a salon chemical.

Care and serviceMaintenance notes

Use the exact maker’s instructions for cleaning, drying, lubrication, adjustment and storage. Do not set tension firmer merely because a blade is labeled SUS440C, or ask for a particular stone finish without reference to the actual edge design.

Give the service provider the model, symptoms and any history of impact or previous sharpening. A maintenance decision should address the assembled tool. This avoids treating an alloy label as a diagnosis or changing the original geometry to fit a generic steel recommendation.

ContextIndustry snapshot

Two official Yasaka pages provide a concrete comparison:

Sources: Yasaka SA-5.5 and SA-5.5 OF. Both listings describe ring inserts; neither reviewed page gives a numerical hardness. The shared overall length and material do not make their blade dimensions identical. Check the exact model suffix when comparing reach or ordering a replacement.

Trade-offs

The useful advantage of a clearly documented designation is traceability: it lets a buyer distinguish a named material from a broad “Japanese steel” claim and ask more precise questions. It does not establish a price tier, a service interval or a guarantee of manufacturing quality based on country alone.

Compare the complete offer: fit, dimensions, stated intended work, care requirements, service access and the detail of the maker’s specification. If hardness is absent, record it as absent. Borrowing a material-reference number would make the product comparison appear more complete while making it less accurate.

Source trailSources

The primary records below cover three distinct subjects: JSSA’s designation comparison, Fukaumi’s named plate data, and Yasaka’s model specifications. All were reviewed on 30 September 2026. The complete normative JIS text was not retrieved; no claim of auditing its full requirements is made.

Related: 440C Stainless • Edge Types • Scissor Maintenance

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