Stainless steel rust appears, there may be several reasons:
Folding existing in the environment of chloride ion
Chloride ion is widespread, such as salt sweat/trace/water/wind/Earth, etc,. Environments of stainless steel in the presence of chloride ions and corrosion soon, even more than ordinary carbon steel. So the use of stainless steel environmental requirements, and the need to frequently wipe, remove dust, clean and dry. (So you can give him a "misuse". ) Is an example of the United States: an enterprise with an oak container containing a solution containing chloride ions, the container has been used the past hundred years, in the last century 90 's plans to replace, because oak is not modern enough, made of stainless steel containers replaced after 16 days for corrosion and leakage.
Collapsed without solution treatment
Alloying elements does not dissolve into the matrix, matrix of low alloy content, poor corrosion resistance.
Intergranular corrosion of folds are born
This titanium and Niobium-containing materials have a tendency to intercrystalline corrosion. Joining of titanium and niobium, coupled with a stable, you can reduce the intergranular corrosion. In the air or chemical corrosion corrosion resistant high alloy steels, the surface of stainless steel is beautiful and good corrosion resistance, color without plating, surface treatment, surface performance of play inherent in stainless steel, used in a wide range of steel, often referred to as stainless steel. Represents the properties of 13 CR steel, chrome-nickel steel, high alloy steel 18-8. From the perspective of metallography, because stainless steel contains chromium and chromium thin film formed on the surface, this membrane isolated from oxygen corrosion of steel into the role. In order to maintain the inherent corrosion resistance of stainless steel, chromium steel must contain more than 12%. Used where welding is required. Lower carbon content makes it near the carbide precipitation in weld heat-affected zone to a minimum, and carbides can cause stainless steel intergranular corrosion in some environments (welding erosion).