If it is oxidation, it means that a thin layer of oxide is formed on the surface. For example, most stainless steel tableware will turn black once heated. If it is corrosion, there will be many tiny pits on the surface, such as acidic food or salt. The first kind of blackening can be maintained by removing rust and brightening with the commercially available "electroplating rust and brightening agent". The second blackening is more difficult to add luster.

304: universal model; Namely 18/8 stainless steel. Products such as: corrosion resistant containers, tableware, furniture, railings, medical equipment. The standard components are 18% chromium and 8% nickel. It is a non-magnetic stainless steel, and its metallographic structure will not be changed by heat treatment. Historical origin:

The invention and use of stainless steel can be traced back to the First World War. At that time, the British guns on the battlefield were always transported back to the rear because the bore was worn and unusable. The Ministry of Military Production ordered Lieutenant Li to develop high-strength wear-resistant alloy steel to solve the problem of gun bore wear. Li and his assistant collected various kinds of steel and alloy steel at home and abroad.

Performance experiments were carried out on various machines with different performances, and then more suitable steel was selected to make guns. One day, they experimented with an alloy steel containing a lot of chromium. After the wear-resistant experiment, it was found that this alloy was not wear-resistant, which indicated that guns could not be made. So they recorded the experimental results and threw things at the corner.

One day a few months later, an assistant came to Bougel with a shiny piece of steel and said, "Sir, this is the alloy steel that Mr. Mullah sent me when I was cleaning the warehouse. Do you want to try it and see what special effect it has? " "good!" Buhrer looked at the bright steel and said happily.