ASTM A790 UNS S31803 Duplex Pipes are nitrogen enhanced duplex pipes which are mainly developed for overcoming the issue of 300 series seamless stainless steel pipes. These pipes are in the range of 316 L and 317 L of 300 series. The term used with these pipes is “duplex” which simply refers to the family of these pipes that have double in the structure. Double structure means they are neither in standard ferric pipes nor fully austenitic SS structure (as present in 304 stainless steel pipes).
There are plenty of certifications to be done with these pipes, they are – EN 10204 3.1/ ISO 10474 3.1/ DIN 500494 3.1 mill tests, NACE MR- 1075/ ISO 15156/ NACE MR-01-03, NACE MR-01-75, European pressure equipment, ASME boiler and pressure vessel code sec.II, and many other national and international standard quality tests and certifications.

If you want to check the best quality of these pipes then verification of their pipe width certification is must. These pipes have various applications also such as they are used in chemical plants, pipe works, structural hollow section, natural gas transportation and many others.

Double protection from corrosion
Duplex stainless steel pipes will show you double resistance from the corrosion to grade 316. They are also good in preventing these pipes from chloride corrosion and other types of cracklings of pipes. They are good in tolerating high temperature and other type of oxidation. But still, they are never used in temperature more than 300°C. ASTM A790 UNS S31803 Duplex Pipes are good in showing resistance to seawater corrosion also.