Stainless steel (Stainless Steel) Refers to the steel which resistance to air, steam, water and other weak corrosive media and acid, alkali, salt and other corrosive chemical corrosion medium, also known as acid-resistant stainless steel. In Practical application ,the corrosion-resistant medium corrosion of steel be called stainless steel , and the corrosion-resistant chemical medium steel be called acid-resistant steel. Due to the difference in chemical composition between the two, the former is not necessarily resistant to chemical corrosion, while the latter generally have a stainless steel. The corrosion resistance of stainless steel depends on the alloying elements contained in the steel.
304 stainless steel is a common material in stainless steel, the density of 7.93 g / cm3, the industry is also called 18/8 stainless steel. High temperature 800 degrees, in order to maintain the inherent corrosion resistance of stainless steel, steel must contain more than 18% chromium, more than 8% nickel content. With good processing performance, high toughness characteristics, widely used in industrial and furniture decoration industry and food and medical industry. Marking the market common methods are 06Cr19Ni10, SUS304, 06Cr19Ni10 which generally show that the national standard production, 304 stainless steel is produced in accordance with the United States ASTM standards of a grade of stainless steel.
The Ti as a stabilizing element in 321 stainless steel , but it is also hot steel, in the high temperature it is much better than the 316L .321 stainless steel has good abrasion resistance in different concentrations, different temperatures of organic acids and inorganic acids, especially in the oxidizing medium.it is widely used in the manufacture of wear-resistant acid containers and wear-resistant equipment lining, transmission pipeline.
321 stainless steel is a Ni-Cr-Ti austenitic stainless steel, its performance is very similar to the 304, but because of the addition of metal titanium, it has a better resistance to grain boundary corrosion and high temperature strength. As the addition of metal titanium, it effectively control the formation of chromium carbide. 321 stainless steel has excellent high temperature stress rupture (Stress Rupture) performance and high temperature creep resistance (Creep Resistance) stress mechanical properties .In this point,it is better than 304 stainless steel.