Semi-stainless steel · ProterialSLD SLD
Also called: SKD11 · D2 · Hitachi SLD
SLD is a stainless semi-stainless steel from Proterial (formerly Hitachi Metals): 1.50% carbon, 12.00% chromium, and a maker hardening hardness of ≥58 HRC. In Knife Steel Nerds’ CATRA edge-retention test it cut 486 mm of card at 60.5 HRC.
Composition
| C | Si | Mn | Cr | Mo | V |
|---|---|---|---|---|---|
| 1.50 | 0.30 | 0.40 | 12.00 | 0.90 | 0.30 |
Mass %. As published by the steelmaker (typical or representative values). Hardness: ≥58 (hardening hardness).
What the data says
SLD is Proterial’s cold-work die steel, which the maker lists as equivalent to JIS SKD11, AISI D2 and W-Nr. 1.2379. Its typical composition is 1.50% carbon, 12.00% chromium, 0.90% molybdenum and 0.30% vanadium, with a hardening hardness of 58 HRC or over.
Proterial describes it as a die steel with high abrasion resistance. Knife Steel Nerds tested the equivalent AISI D2: 486 mm in the CATRA test at 60.5 HRC.
With 12% chromium it resists rust better than the paper steels, but it is a tool steel rather than a stainless knife steel, and knives in SLD are commonly described as “semi-stainless”.
SLD compared with similar steels
| Steel | Type | C % | Cr % | Maker HRC | CATRA mm |
|---|---|---|---|---|---|
| SLD (≈ D2 / SKD11) | Semi-stainless | 1.50 | 12.00 | ≥58 | 486 @ 60.5 |
| HAP40 | Powder high-speed · PM | 1.27–1.37 | 3.70–4.70 | 64–66 or 66–68, depending on quench temperature | — |
| Ginsan (Silver #3) | Stainless | 0.95–1.10 | 13.00–14.50 | ≥59 | — |
| VG-10 | Stainless | 1.00 | 15.00 | ≥60 | 479 @ 61.6 |
See all 15 steels in the Japanese knife steel chart, or compare up to three at once in the steel explorer.
Care
SLD is a stainless steel, so occasional wetness will not rust it the way it rusts a carbon steel, but washing by hand and drying it keeps the edge and handle in good condition.
Buying a SLD knife from a shop in Japan? Japanese kitchen knives currently pay about 31% US import duty — use the import duty calculator to compare with a US retailer.
Frequently asked questions
- Is SLD stainless?
- Yes. SLD contains 12.00% chromium, above the roughly 10.5% that defines a stainless steel.
- How hard is SLD?
- Proterial publishes a hardening hardness of ≥58 HRC. The hardness of a finished knife depends on the knifemaker’s heat treatment.
- Who makes SLD?
- SLD is made by Proterial (formerly Hitachi Metals).
- SLD vs HAP40: what is the difference?
- SLD: C 1.50%, Cr 12.00%, maker hardness ≥58 HRC. HAP40: C 1.27–1.37%, Cr 3.70–4.70%, maker hardness HRC 64–66 or 66–68, depending on quench temperature.
Sources
Checked 2026-10-21. Found a better source or an error? Tell us.