HOME > MAINTENANCE > Mechanism of Rust What is stainless steel? An alloy with at least 10.5% chrome is called stainless steel. Elements other than chrome are also included in stainless steel. Carbon for example, is needed for the heating process to make stainless steel hard enough to be used in knives. (The higher the carbon component, the harder the stainless steel becomes during the heating process, however this makes it more susceptible to rusting). There is a variety of stainless steel types featuring various characteristics, including those that contain nickel, molybdenum and vanadium, and those that display characteristics such as toughness and corrosion resistance. Why stainless steel is rust resistant? When stainless steel is exposed to the air, chrome amalgamates with oxygen and forms a thin film (passive film) over the steel, which prevents rust from generating. This prevents dirt or steel from sticking to oxygen or liquid (which causes rust). Why stainless steel rusts? If the knife is unclean or wet, the chrome cannot get in touch with oxygen and the protective film will not be created. The direct coupling of steel and oxygen/water causes rusts. Knives will also rust for the same reason when they are stored in damp conditions. Why the dishwasher/dryer can't be used? As the water is circulated during washing and rinsing, a lot of miniscule residues will remain, preventing the protective film from forming on the knife. Moreover, rusting will accelerate if the knife is dried at high temperature in this circumstance. Alkaline detergent used for dishwashers is also harmful to stainless steel. We recommend hand washing of the knife with neutral detergent and drying it thoroughly before storing.