The advantages and development of stainless steel
Stainless steel jewelry is a very special metal jewelry, the texture is very tough, but it is very corrosion-resistant. It will not turn black like silver, nor is it prone to allergies like copper jewelry, and it will not be like alloy jewelry. Leaded and toxic, stainless steel jewelry always retains its color tone for life at room temperature. Stainless steel jewelry is made of the same material from the inside to the outside, and has passed the artificial sweat test. Its characteristics are that it is completely non-corrosive, and is resistant to strong acid and alkali. It is a green high-grade environmental protection jewelry that will not produce any side effects and harmless to the human body.
The corrosion resistance of stainless steel jewelry depends on the alloying elements contained in the steel. Chromium is the basic element for stainless steel to obtain corrosion resistance. When the chromium content in steel reaches about 12%, chromium and oxygen in the corrosive medium act to form a thin oxide film (self-passivation film) on the steel surface. , which can prevent further corrosion of the steel matrix. In addition to chromium, the commonly used alloying elements are nickel, molybdenum, titanium, niobium, copper, nitrogen, etc., to meet the requirements of various uses for the structure and properties of stainless steel. Its corrosion resistance, toughness and weldability increase with the increase of chromium content, and its resistance to chloride stress corrosion is better than other types of stainless steel.
Stainless steel is a modern material with a development history of more than 60 years. Since stainless steel jewelry began to appear in recent years, stainless steel has combined the image of modern materials and the excellent reputation in jewelry application. As long as the steel is correctly, processed properly, and maintained Fit, stainless steel jewelry won't corrode, pit, rust, or wear out, making it the envy of its competitors.
stainless steel pitting
Pitting corrosion of stainless steel mostly occurs in aqueous environments containing iodine, chlorine, and bromine. The reason for the pitting corrosion of stainless steel is that chloride ion is an active anion, which is easily adsorbed, squeezes out oxygen atoms, and reacts with cations in the passivation film to form soluble chloride, which destroys the passivation film, forms small pores, and becomes a pitting inducement stage. , at this stage, a closed circuit is formed, and the phenomenon of current corrosion occurs.
1. Select the appropriate stainless steel material in an environment where pitting corrosion is known to occur. Experiments show that the higher the content of molybdenum (Mo) or manganese (Mn), the stronger the resistance to pitting corrosion;
2. Control the pH, chloride concentration and temperature of the liquid in contact with stainless steel;
3. Cathodic protection, anodic protection or both protection measures;
4. Use better quality stainless steel as much as possible, such as 316 or 316L, to improve the pitting corrosion resistance of stainless steel pipes.