Can anyone tell me what that means. I have seen it on knife blades an such. I am assuming it's a formula for the strength of the metal. who does that scale work, and please keep it simple.
The number just indicates which class of steel alloy it belongs. Yours happens to be a 400 series and happens to have no Nickel in it (440 Steel) and a higher amount of carbon (Nickel is very common in steel) When I say alloy, I'm referring to the different chemical formulas and processing of steel which vary for different uses like industrial use, medical use or decorative use. Think of the different alloys like the types of soft drinks out there. Coke, Pepsi and Dr. Pepper. They all have very similar chemical formulas; yet differ with their secret ingredients which is apparent in the taste.
440 is an AISI (American Iron and Steel Institute) material specification. It specifies the precise quantities of carbon and other elements present in the alloy. Here are the constituents of AISI 440 steel: Carbon - 0.6 to 0.75% Chromium - 16 to 18% Manganese - less than 1% Molybdenum - less than 0.75% Phosphorus - less than 0.04% Silicon - less than 1% Sulfur - less than 0.03% Iron makes up the remainder. AISI 440 is a heat-treatable, precipitation-hardening stainless steel.
