S-STAR is a high-purity martensitic stainless steel produced by Daido Steel primarily for plastic injection molds and corrosion-resistant tooling. Manufactured using ESR (Electro-Slag Remelting), it features excellent cleanliness, uniform carbide distribution, and superior corrosion resistance compared to conventional stainless steels. Although originally designed as a mold steel, several Japanese knife makers have successfully adapted S-STAR for knife production because of its fine grain structure, toughness, and excellent resistance to staining and rust. In knife applications, S-STAR is often compared to a highly refined version of 420HC or 12C27, prioritizing corrosion resistance and edge stability over extreme wear resistance.
Comparable Steels:
S-STAR > 420HC in corrosion resistance and steel cleanliness
S-STAR > X46Cr13 (1.4034) in corrosion resistance
S-STAR ≈ 12C27 in real-world knife performance
S-STAR ≈ AEB-L in toughness and edge characteristics
S-STAR < VG-10 in wear resistance
S-STAR < CPM-S30V in edge retention
S-STAR < MagnaCut in overall performance
S-STAR > H1 and LC200N in edge retention, but trails them in corrosion resistance under extreme saltwater conditions
Equivalent / Similar Steels:
AEB-L
12C27
14C28N
420HC (high-end heat treated)
Böhler N680 (application overlap)
Typical Composition (Approximate):
Carbon (C): ~0.38%
Chromium (Cr): ~13.5%
Molybdenum (Mo): ~0.30%
Nickel (Ni): Trace additions
Manganese (Mn): ~0.50%
Silicon (Si): ~0.90%
Note:
S-STAR is not a conventional knife steel and was originally engineered for high-polish corrosion-resistant mold applications. However, its exceptional cleanliness, stainless properties, and fine-grained structure have made it increasingly popular among Japanese knife makers seeking a highly corrosion-resistant alternative to traditional stainless steels.