The Periodic Table of Knife Steel
What each element does inside a blade, and the Knives & Stones steels that lean on it.
C Carbon
主要硬化元素。提高硬度與耐磨性，但過多會增加脆性與鏽蝕傾向。
Carbon is the backbone of edge performance: it lets the steel reach high hardness and forms the carbides that resist wear. The trade-off is real — high-carbon steels are less forgiving and, uncombined with chromium, rust more readily.
N Nitrogen
可替代碳作為硬化元素。在特殊鋼材中改善耐蝕性與耐磨性。
Nitrogen behaves a lot like carbon for hardening but can boost corrosion resistance, which is why it defines modern "nitrogen steels." Niche today, but distinctive where used.
K&S steel data for this element is being sourced.
Si Silicon
強化鋼基質並作為脫氧劑。改善硬度與抗氧化性。
Silicon firms up the matrix and helps temper resistance; like manganese it also deoxidises the melt. Present in nearly every blade steel in small amounts.
P Phosphorus
冶煉過程中的雜質。即使少量也會造成脆性，鋼廠盡可能降低含量。
Phosphorus is a residual from the smelting process. It promotes brittleness, so clean steels hold it to a few hundredths of a percent at most.
K&S steel data for this element is being sourced.
S Sulfur
降低韌性並促進脆性的雜質。僅在快削鋼中刻意添加。
Sulfur lowers toughness and is kept very low in blade steels — the cleanest paper steels hold it near 0.004%. It is added on purpose only in free-machining grades, which knives avoid.
K&S steel data for this element is being sourced.
V Vanadium
形成極硬碳化物，提供優異的持鋒性。同時細化晶粒結構，改善韌性。
Vanadium punches above its weight: small amounts form very hard carbides that resist wear and pin grain growth in heat treatment, keeping the edge fine. The cost is sharpening effort on the stones.
Cr Chromium
提高耐蝕性；13%以上即為不鏽鋼。同時改善淬透性與耐磨性。
Chromium is what makes a steel "stainless." It also forms hard chromium carbides that aid wear resistance. In the kitchen, very high chromium can add a faint drag on the cut — the trade for rust resistance.
Mn Manganese
有助於淬透性與強度。在冶煉過程中作為脫氧劑。過多會降低韌性。
Manganese helps the steel harden predictably and cleans the melt as a deoxidiser and desulfuriser. A deliberate, if unglamorous, alloying element present in nearly every steel.
Co Cobalt
允許更高的硬化溫度，增加硬度與耐磨性。高含量時稍微降低韌性。
Cobalt doesn't form carbides itself; it strengthens the matrix and raises attainable hardness, which is why it appears in some high-end stainless grades such as VG-10. A little reduces toughness at the top end.
Ni Nickel
改善韌性與延展性而不犧牲硬度。稍微提高耐蝕性。
Nickel toughens — most visible in clad / san-mai construction and some stainless grades. It doesn't form carbides; it works in the matrix.
K&S steel data for this element is being sourced.
Cu Copper
大多數刀用鋼中的附帶雜質。稍微提高耐蝕性；控制在低含量以避免熱脆性。
Copper rarely headlines a blade alloy. Where it's deliberate it nudges corrosion resistance; more often it's an incidental residual from the melt. We keep the copy honest rather than overstating a "virtue."
K&S steel data for this element is being sourced.
Nb Niobium
Forms some of the hardest carbides in steel — even finer than vanadium's — for wear resistance and strong grain refinement.
Niobium is a powerful carbide-former and grain refiner used in modern powder steels. Its carbides are extremely hard and very fine, supporting both edge retention and a clean, refined edge.
K&S steel data for this element is being sourced.
Mo Molybdenum
改善淬透性與韌性。增加耐蝕性，有助於鋼材在高溫下保持硬度。
Molybdenum makes steels deeper-hardening and tougher, and supports pitting-corrosion resistance in stainless grades. It's a quiet workhorse rather than a headline carbide-former.
W Tungsten
形成硬碳化物，提高耐磨性與持鋒性。即使在高溫下也能保持硬度。
Tungsten carbides are extremely hard, lifting wear resistance and edge stability. It is the defining addition of the Blue (Aogami) paper steels over their White (Shirogami) counterparts.