青紙一號 / 青紙 #1 Blue #1 鋼

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.

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.

Forms hard carbides for wear resistance and edge retention. Gives the steel hardness even at elevated temperatures.

Aids hardenability and strength. Acts as a deoxidiser during smelting. Excess can reduce toughness.

Strengthens the steel matrix and acts as a deoxidiser. Improves hardness and resistance to oxidation.

Impurity from the smelting process. Even small amounts cause brittleness — steelmakers keep this as low as possible.

Impurity that reduces toughness and promotes brittleness. Intentionally added only in free-machining steels.