Basic knowledge of the use of stainless steel tubes

Stainless steel welded pipe is mainly used for heat exchanger pipe, fluid pipe, pressure piping, mechanical structure pipe, cityscape, and other industries, the annual consumption of about 700,000t.Industrial stainless steel welded pipe demand is relatively high, and the production process is mature, at present, China's annual industrial stainless steel welded pipe amount of about 150,000t or so, part of the still need to import. Belonging to this category are Crl7, Cr17Mo2Ti, Cr25, Cr25Mo3Ti, Cr28 and so on. Ferritic stainless steel because of the high chromium content, corrosion resistance and antioxidant properties are relatively good, but the mechanical properties and process performance is poor, mostly used in the acid-resistant structure of the force is not big and for the use of antioxidant steel. This type of steel can resist the atmosphere, nitric acid and brine solution corrosion, and has a good high temperature oxidation resistance, small coefficient of thermal expansion, etc., used in nitric acid and food factory equipment, can also make parts working at high temperature, such as gas turbine parts.
Austenitic stainless steel: contains more than 18% chromium, also contains about 8% nickel and a small amount of molybdenum, titanium, nitrogen and other elements. Comprehensive performance is good, can resist a variety of media corrosion. Austenitic stainless steel commonly used grades are 1Cr18Ni9, 0Cr19Ni9, etc. 0Cr19Ni9 steel wC <0.08%, the steel number marked as "0". This type of steel contains a large amount of Ni and Cr, so that the steel is austenitic at room temperature. This type of steel has good plasticity, toughness, weldability and corrosion resistance, corrosion resistance in oxidizing and reducing media are better, used to make acid-resistant equipment, such as corrosion-resistant containers and equipment lining, piping, nitric acid-resistant equipment parts. Austenitic stainless steel is generally solid solution treatment, that is, the steel is heated to 1050 ~ 1150 ℃, and then water-cooled, 304 stainless steel pipe to obtain single-phase austenitic organization.