Semi-Stainless
Semi-Stainless Steel
Semi-stainless steels sit between carbon and full stainless. They will rust if left wet or neglected, but under normal use they tend to develop a patina — a dark, protective layer — rather than forming aggressive surface rust. Rinse and wipe dry after use and you will rarely have issues. Much more forgiving than true carbon steel, while still offering excellent cutting performance. PM / Powder Steel 분말야금(PM)
PM stands for powder metallurgy. Fine steel powder is consolidated under heat and pressure. This can produce a fine, even carbide structure, but performance still depends on the steel and its heat treatment. The PM label alone does not guarantee a harder, tougher or more chip-resistant knife. 히타치 특수강, 일본
Semi-stainless steels sit between carbon and full stainless. They will rust if left wet or neglected, but under normal use they tend to develop a patina — a dark, protective layer — rather than forming aggressive surface rust. Rinse and wipe dry after use and you will rarely have issues. Much more forgiving than true carbon steel, while still offering excellent cutting performance. PM / Powder Steel 분말야금(PM)
PM stands for powder metallurgy. Fine steel powder is consolidated under heat and pressure. This can produce a fine, even carbide structure, but performance still depends on the steel and its heat treatment. The PM label alone does not guarantee a harder, tougher or more chip-resistant knife. 히타치 특수강, 일본
HAP-40 분말 하이스강 HAP-40
Hardness
Rockwell C Hardness(HRC) 는 강철이 영구 변형에 얼마나 강한지를 나타냅니다. 주방용 칼의 경우:
55–58 HRC — Soft. Easy to sharpen and forgiving of rough use, but dulls faster. Typical of most German knives.
59–61 HRC — Balanced. Good edge retention with manageable sharpening. Common in mid-range Japanese knives.
62–64 HRC — Hard. Excellent edge retention, holds a very fine edge. Requires more care and a fine stone to sharpen.
65+ HRC — Very hard. Exceptional edge longevity but more brittle — more prone to chipping if used roughly.
Higher is not always better — it depends on how you use and maintain your knife.
55–58 HRC — Soft. Easy to sharpen and forgiving of rough use, but dulls faster. Typical of most German knives.
59–61 HRC — Balanced. Good edge retention with manageable sharpening. Common in mid-range Japanese knives.
62–64 HRC — Hard. Excellent edge retention, holds a very fine edge. Requires more care and a fine stone to sharpen.
65+ HRC — Very hard. Exceptional edge longevity but more brittle — more prone to chipping if used roughly.
Higher is not always better — it depends on how you use and maintain your knife.
64–68
HRC
555759616365+
HAP-40 강은 뛰어난 절단력 유지와 내구성으로 유명한 고속도 공구강으로 주방칼에 이상적입니다. 최대 HRC 68의 높은 경도를 달성하여 장기간 사용에도 날카로움을 유지합니다. 탄소, 크롬 및 텅스텐, 바나듐 등의 원소가 혼합되어 경도와 인성의 균형을 이루며 칼날 깨짐 위험을 줄여줍니다. 우수한 내마모성으로 장기적인 성능을 보장하지만, 높은 경도로 인해 연마 시 고급 도구가 필요할 수 있습니다. 조리 도구에 있어 절단 효율과 최소한의 관리를 중시하는 사용자들에게 적합한 강재입니다.
Composition
HAP-40 Element Composition
Compare with
HAP-40
—
8.0%
6.0%
4.0%
2.0%
0
C
1.3%
Cr
4.0%
V
3.0%
Mo
4.8%
W
6.0%
Co
8.0%
C — Carbon
Cr — Chromium
V — Vanadium
Mo — Molybdenum
W — Tungsten
Co — Cobalt
Typical values from third-party sources.
Hardness
64–68 HRC
555759616365+
HAP-40 Composition
What's in HAP-40
What each element does in your knife.
| Element | Composition | What it does in your knife |
|---|---|---|
| CoCobalt | 7.5–8.5% | Allows higher hardening temperatures for more hardness and wear resistance, and strengthens the steel matrix. |
| WTungsten | 5.6–6.5% | Forms hard carbides for wear resistance and edge stability, and keeps the steel hard even at elevated temperatures. |
| MoMolybdenum | 4.6–5.4% | Improves hardenability and toughness, boosts corrosion resistance, and helps the steel hold hardness under heat. |
| CrChromium | 3.7–4.7% | Raises corrosion resistance; at roughly 13%+ free chromium the steel qualifies as stainless. Also improves hardenability and wear. |
| VVanadium | 2.8–3.3% | Forms extremely hard vanadium carbides for superior edge retention, and refines the grain for a finer, tougher edge. |
| CCarbon | 1.27–1.37% | The primary hardening element. More carbon means a harder edge that holds longer — but past a point it trades away toughness and rust resistance. |
Composition from zknives (K&S steel dataset) reference material. These ranges come from the K&S steel composition dataset, which is derived from zknives; maker figures are cited separately only when they are used on the page.
HAP-40 Buying Guide
Should you buy HAP-40?
Where it shines
- “Most standard grade with good balance of hardness, toughness and wear resistance” — per Proterial
- “Hardening hardness ( HRC ) (1)66-68 (2)64-66” — per Proterial
