51315-5703-Corrosion Performances of Modified Grade-Duplex Stainless Steel for Line Pipe Usage in Slightly Sour Environment

Available for download

Product Number: 51315-5703-SG

ISBN: 5703 2015 CP

Author: Masayuki Sagara

Publication Date: 2015

Member Price: $0.00

Non Member Price: $0.00

Price: $0.00

Qty:

The CRAs (corrosion resistant alloys) have been widely used as line pipes because of its availability workability and corrosion resistance. Those are used for the flow line material in the corrosive wet gas i.e. carbon dioxide and hydrogen sulfide environment.Recently a new duplex stainless steel which consists of 25mass%Cr -5mass%Ni -1mass%Mo -2.5mass%Cu has been developed. Chromium and copper are alloyed because it can be considered that these elements can be the alternative elements instead of molybdenum to enhance the corrosion resistance. The developed material can provide sufficient SSC resistance in slightly sour environment in spite of smaller molybdenum content than that of existing duplex grades such as UNS S31803 (22Cr conventional duplex stainless steels). Post weld heat treatment is mandatory for weldable 13Cr line pipes but the welded joints without PWHT of developed material show the sufficient SCC resistance at elevated temperature as well as the SSC resistance at intermediate temperature 90degC. The temperature dependence of most susceptible to cracking is also investigated in this study. The purposes of this research are to confirm the effect on SSC resistance at as-welded portion in slightly sour environment and to evaluate the susceptibility to SCC at intermediate and elevated temperature.Key words: CRA Flow line Copper Chromium Molybdenum Duplex stainless steel Stress corrosion cracking Sulfide stress cracking Hydrogen sulfide Weld.