Wenzhou duplex stainless steel pipe because of its special advantages, widely used in petrochemical facilities, water and wastewater treatment equipment, oil pipelines, papermaking machinery and other industrial areas, recent research has also been used in the field of bridge load-bearing structure. First, the thicker the wall thickness of the product, it is more economical and practical, thinner wall thickness, plus its duplex stainless steel pipe has good weldability, and ferritic stainless steel and austenitic stainless steel phase ratio, both HAZ unlike ferritic stainless steel, due to severe grain coarsening leaving plastic toughness significantly reduced, unlike austenitic stainless steel, as more sensitive to weld hot cracking. . Wenzhou advantages of duplex stainless steel pipe: 1, with wall thickness of duplex stainless steel tank or pressure vessel than the usual 30-50% reduction in austenite, help reduce costs. 2, and carbon steel close for connection with steel, has important engineering significance, such as the production of composite panels or linings. Stress corrosion is a common austenitic stainless outstanding problems difficult to solve. 3, no matter under dynamic loading or static load conditions, with higher energy absorption capacity, which structure to cope with incidents such as collisions, explosions and other obvious advantages of duplex stainless steel, have practical value. 4, duplex stainless steel pipe with good resistance to localized corrosion, its resistance to corrosion and abrasion are superior corrosion fatigue of austenitic stainless steel. 5, with the ability to excellent resistance to stress corrosion cracking, even the lowest-containing duplex stainless steel alloy also has a higher capacity than the austenitic stainless steel resistance to stress corrosion cracking, especially chlorine ions in the environment.