The rust phenomenon of stainless steel materials may have the following reasons:
Chloride ions are present in the environment of use
According to the introduction of stainless steel parts processing plants, chloride ions are widespread, such as salt/sweat traces/sea water/sea breeze/soil and so on. Stainless steel corrodes quickly in the presence of chloride ions, even exceeding that of ordinary low-carbon steel. Therefore, there are requirements for the use environment of stainless steel, and it needs to be wiped frequently to remove dust and keep it clean and dry. (In this way, you can give him an “improper use”.) There is an example in the United States: a company used an oak container to hold a solution containing chloride ions. The container has been used for nearly a hundred years, and it was planned to be replaced in the 1990s. Because the oak material is not modern enough, the container leaked due to corrosion 16 days after the replacement of stainless steel.
No solution treatment
The alloying elements are not dissolved into the matrix, resulting in low alloy content of the matrix structure and poor corrosion resistance.
Inherent intergranular corrosion
The stainless steel parts processing plant said that this material that does not contain titanium and niobium has a tendency to intergranular corrosion. Adding titanium and niobium, together with stabilization treatment, can reduce intergranular corrosion. A high-alloy steel that can resist corrosion in the air or in chemically corrosive media. Stainless steel has a beautiful surface and good corrosion resistance. It does not need to undergo surface treatment such as plating, but uses the inherent surface properties of stainless steel. It is used in many applications. A kind of steel, usually called stainless steel. High-alloy steels such as 13 chrome steel and 18-8 chrome-nickel steel represent performance. From a metallographic point of view, because stainless steel contains chromium, a very thin chromium film is formed on the surface. This film isolates the oxygen from the intrusion of the steel and acts as a corrosion resistance. According to the stainless steel parts processing plant, in order to maintain the inherent corrosion resistance of stainless steel, steel must contain more than 12% chromium. Used in occasions where welding is required. The lower carbon content minimizes the precipitation of carbides in the heat-affected zone near the weld, and the precipitation of carbides may cause stainless steel to produce intergranular corrosion (welding erosion) in certain environments.