Stainless steel (Stainless Steel) is a type of steel. The content of carbon (C) below 2% is called steel, and more than 2% is iron. The corrosion resistance of stainless steel depends on the alloying elements contained in the steel. Chromium is the basic element for the corrosion resistance of stainless steel. When the chromium content in the steel reaches about 12%, the chromium chemically reacts with the oxygen in the corrosive medium, forming a thin oxide film (passivation film) on the surface of the steel. ) To prevent further corrosion of the steel matrix. In addition to chromium, commonly used alloying elements include nickel, molybdenum, titanium, niobium, copper, nitrogen, etc., to meet the requirements of various uses for the structure and performance of stainless steel.