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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. Hitachi Special Steel, Japan 🇯🇵

SKD

Hardness ? Rockwell C Hardness (HRC) measures how resistant a steel is to permanent deformation. For kitchen knives:

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.
62–64 HRC
555759616365+
SKD short for SKD12 also known as A2 tool steel, with about 1% of Carbon content, and only 4.5% of Chromium. It can be treated to about 63 to 64.

The SKD very much behaves like carbon steel in terms of taking a very keen edge, the food release and also super easy to sharpen; yet without the need of high maintenance. As a result it is very popular amongst professional chefs.

Yoshikane is the noteable compnay that loves the SKD.
Composition

SKD Element Composition

Compare with
    SKD
    —
    5.0% 3.8% 2.5% 1.3% 0
    C Carbon 1.0%
    Primary hardening element. Raises hardness and wear resistance — but too much increases brittleness and corrosion susceptibility. As a reference: German 1.4112 (~0.5%) sits at the low end; VG-10 (~1.0%) is a common mid-range; SG2 (1.25–1.45%) and ZDP-189 (~3.0%) represent high and extreme ends respectively.
    C
    1.0%
    Cr Chromium 5.0%
    Raises corrosion resistance; 13%+ qualifies steel as stainless. Also improves hardenability and wear resistance. In kitchen use, higher chromium levels contribute to a slight drag or sticking sensation when cutting — a trade-off for the rust resistance it provides.
    Cr
    5.0%
    V Vanadium 0.35%
    Forms extremely hard carbides for superior edge retention. Also refines grain structure, improving toughness.
    V
    0.35%
    Mo Molybdenum 1.0%
    Improves hardenability and toughness. Boosts corrosion resistance and helps the steel hold hardness under heat.
    Mo
    1.0%
    Mn Manganese 0.7%
    Aids hardenability and strength. Acts as a deoxidiser during smelting. Excess can reduce toughness.
    Mn
    0.7%
    Si Silicon 0.4%
    Strengthens the steel matrix and acts as a deoxidiser. Improves hardness and resistance to oxidation.
    Si
    0.4%
    P Phosphorus 0.03%
    Impurity from the smelting process. Even small amounts cause brittleness — steelmakers keep this as low as possible.
    P
    0.03%
    S Sulfur 0.03%
    Impurity that reduces toughness and promotes brittleness. Intentionally added only in free-machining steels.
    S
    0.03%
    Cu Copper 0.25%
    Incidental impurity in most knife steels. Slight boost to corrosion resistance; kept low to avoid hot-shortness.
    Cu
    0.25%
    Ni Nickel 0.5%
    Improves toughness and ductility without sacrificing hardness. Adds a small boost to corrosion resistance.
    Ni
    0.5%
    C — Carbon Cr — Chromium V — Vanadium Mo — Molybdenum Mn — Manganese Si — Silicon P — Phosphorus S — Sulfur Cu — Copper Ni — Nickel
    Hardness 62–64 HRC
    555759616365+
    Steel
    SKD
    Category
    Semi-stainless
    Manufacturer
    Hitachi Special Steel, Japan 🇯🇵
    Hardness
    62–64 HRC

    Knives in SKD

    View all
    Hatsukokoro x Yoshikane SKD Nashiji Honesuki 150mm Ebony Handle

    Hatsukokoro

    Hatsukokoro x Yoshikane SKD Nashiji Honesuki 150mm Ebony Handle

    $12,460.00
    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 210mm Extra Tall, Bocote Handle
    Sold Out

    Yoshikane

    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 210mm Extra Tall, Bocote Handle

    $16,152.00
    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 210mm Extra Tall, Heart-shaped Ebony Handle
    Sold Out

    Yoshikane

    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 210mm Extra Tall, Heart-shaped Ebony Handle

    $16,152.00
    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 210mm Extra Tall, Cosmic Swirl Handle
    Sold Out

    Yoshikane

    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 210mm Extra Tall, Cosmic Swirl Handle

    $16,152.00
    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 210mm Extra Tall, Argetine Lignum Handle
    Sold Out

    Yoshikane

    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 210mm Extra Tall, Argetine Lignum Handle

    $16,152.00
    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 210mm Extra Tall, Copper Mesh Handle
    Sold Out

    Yoshikane

    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 210mm Extra Tall, Copper Mesh Handle

    $16,152.00
    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 210mm Extra Tall, Stablized Burl Handle
    Sold Out

    Yoshikane

    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 210mm Extra Tall, Stablized Burl Handle

    $16,152.00
    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 240mm Extra Tall, with Magnetic Guard
    Sold Out

    Yoshikane

    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 240mm Extra Tall, with Magnetic Guard

    $17,998.00
    Hatsukokoro x Yoshikane SKD Nashiji K-tip Gyuto 240mm Ebony Handle

    Hatsukokoro

    Hatsukokoro x Yoshikane SKD Nashiji K-tip Gyuto 240mm Ebony Handle

    $14,999.00
    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 240mm Ebony Handle

    Yoshikane

    Hatsukokoro x Yoshikane SKD Nashiji Gyuto 240mm Ebony Handle

    $13,614.00
    Hatsukokoro x Yoshikane SKD Nashiji K-tip Gyuto 210mm Ebony Handle

    Yoshikane

    Hatsukokoro x Yoshikane SKD Nashiji K-tip Gyuto 210mm Ebony Handle

    $12,922.00
    Hatsukokoro x Yoshikane SKD Nashiji Bunka 165mm Ebony Handle

    Yoshikane

    Hatsukokoro x Yoshikane SKD Nashiji Bunka 165mm Ebony Handle

    $10,614.00
    Hatsukokoro x Yoshikane SKD Nashiji Petty 150mm Ebony Handle
    Sold Out

    Yoshikane

    Hatsukokoro x Yoshikane SKD Nashiji Petty 150mm Ebony Handle

    $8,999.00
    Hatsuokokoro x Yoshikane SKD Nashiji Sujihiki 240mm Ebony Handle

    Yoshikane

    Hatsuokokoro x Yoshikane SKD Nashiji Sujihiki 240mm Ebony Handle

    $13,153.00
    Hatsuokokoro x Yoshikane SKD Nashiji Gyuto 210mm Ebony Handle

    Yoshikane

    Hatsuokokoro x Yoshikane SKD Nashiji Gyuto 210mm Ebony Handle

    $11,768.00
    Yoshikane SKD Nashiji Nakiri 165mm Stainless Clad Ebony Handle

    Hatsukokoro

    Yoshikane SKD Nashiji Nakiri 165mm Stainless Clad Ebony Handle

    $10,383.00
    Hatsukokoro x Yoshikane SKD Nashiji Santoku 170mm Ebony Handle

    Yoshikane

    Hatsukokoro x Yoshikane SKD Nashiji Santoku 170mm Ebony Handle

    $9,922.00
    Our Locations

    Visit Us In Person

    Experience our knives hands-on at any of our three showrooms across Australia.

    St Peters

    HQ
    Unit 2, 2 Bishop St
    St Peters, NSW 2044
    (02) 8234 8818 sales@knivesandstones.com.au
    Mon–Fri 10am–5pm Closed weekends

    Enter via Bishop St. Limited parking — please find nearby street parking.

    Get directions

    Crows Nest

    Open Weekends
    107 West St
    Crows Nest, NSW 2065
    (02) 8234 8848
    Mon, Tue, Fri, Sat, Sun 10am–6pm Closed Wed & Thu
    Get directions

    Canberra

    Kakumei
    Unit 3, 32 Lonsdale St
    Braddon, ACT 2612
    (02) 8234 8808
    Wed–Thu 10:30am–4:30pm Fri–Sat 10:30am–6pm Sun 10:30am–4:30pm Closed Mon & Tue
    Get directions
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