ASTM A789 Seamless and Welded Stainless Steel Tubing
The duplex stainless steel tube has good welding performance. Compared with ferritic stainless steel and austenitic stainless steel, it is not like the welding heat affected zone of ferritic stainless steel, and the plastic toughness is greatly reduced due to severe grain coarsening.
The duplex stainless steel tube has good welding performance. Compared with ferritic stainless steel and austenitic stainless steel, it is not like the welding heat affected zone of ferritic stainless steel, and the plastic toughness is greatly reduced due to severe grain coarsening. Nor is it sensitive to hot cracking of welds like austenitic stainless steel.
Due to its special advantages, duplex stainless steel is widely used in petrochemical equipment, seawater and wastewater treatment equipment, oil and gas pipelines, papermaking machinery and other industrial fields. In recent years, it has also been studied in the field of bridge load-bearing structures. Prospects.
Duplex stainless steel is half of the ferrite phase and austenite phase in its solidified structure, and the minimum phase content may be up to 30%.
Duplex stainless steel
The first type is a low-alloy type, representing the grade UNS S32304 (23Cr-4Ni-0.1N). The steel contains no molybdenum and has a PREN value of 24-25. It can be used in place of AISI304 or 316 in terms of stress corrosion resistance. The second type is a medium alloy type, the representative grade is UNS S31803 (22Cr-5Ni-3Mo-0.15N), the PREN value is 32-33, and its corrosion resistance is between AISI 316L and 6% Mo+N austenitic stainless steel.
The third type is a high alloy type, generally containing 25% Cr, also containing molybdenum and nitrogen, and some also containing copper and tungsten, standard grade UNSS32550 (25Cr-6Ni-3Mo-2Cu-0.2N), PREN value of 38-39 The corrosion resistance of this type of steel is higher than that of 22% Cr duplex stainless steel. The fourth category is super duplex stainless steel type, containing high molybdenum and nitrogen, standard grade UNS S32750 (25Cr-7Ni-3.7Mo-0.3N), and some also contain tungsten and copper, PREN value is greater than 40, can be applied to harsh The medium condition has good corrosion resistance and mechanical comprehensive performance, which is comparable to super austenitic stainless steel.
S31803/S32205, S32750, S32760, S31500, S32001, S32003, S32304
★ASTM A789 Seamless and Welded Stainless Steel Tubing
★ASTM A790 (ASME SA790) Seamless and Welded Stainless Steel Pipe
★ASTM A928 (ASME SA928) (Duplex) Stainless Steel Pipe
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