What is Duplex Stainless Steel Pipe

what is duplex stainless steel pipe?

duplex stainless steel (dss) including grades duplex 2205(s31803) and super duplex, they are commonly consist of 50% ferrite and 50% austenite, and generally requires not less than 30%. duplex stainless steel has good welding performance and high strength. compared with austenitic stainless steel, it is about double yield strength of stainless steel 316, 317 etc., it make the equipment lighter and stronger. duplex stainless steel pipe has very good resistance to localized corrosion and stress corrosion cracking. duplex steel is not intended to be used at temperatures above 300°c due to embrittlement, the continuous use temperature is from -50 to 250 °c.

duplex and super duplex grade:

duplex stainlss steel saf 2205(uns s32205, s31803), super duplex saf 2507 (uns s32750), s32760, s32304 etc.

saf 2205 is the most common grade for duplex stainless steel, asme/astm grade is uns s32205 or the similar grade s31803 , equivalent to en/din 1.4462.

saf 2507 is a super duplex steel, the astm grade is s32750, equivalent to en/din 1.4410. we can supply duplex pipes and fittings with high quality , mill cost and fast delivery time.

duplex 2205 and super duplex 2507 is the common grade for us. for other grades, we can manufacturing and provide at considerable order quantity.

what is pren for duplex and super duplex pipe

what is pren - pitting resistance equivalent number, abbreviated as pren, is a set of algorithms calculated on the basis of the mass fraction of certain elements in the metal. the value is often used in the evaluation method for comparison of pitting corrosion resistance.

there is a formula for pren calculating:

pren=cr%+3.3 *（mo+0.5w）%+16 *n%

as per astm a790, pren of 22 cr duplex 2205 pipe is >31, and 25 cr super duplex pipe is more than 40. if you have special requirement, you are welcome to contact us, our factory can accept customized fabrication.