The lean duplex material UNS S32202 was developed to provide a cost-efficient alternative to the austenitic stainless steel UNS S30403. This grade is today widely used for various applications in the pulp & paper and water industries. UNS S32202 presents a resistance equal or better than UNS S30403 for uniform, localized (pitting and crevice) and intergranular corrosion.
This paper focuses on the stress corrosion cracking and sulfide stress cracking resistance of UNS S32202 in sour environments. Recent results obtained in solutions containing chlorides and H2S by means of proof-ring and constant load tests are provided and an application window for this grade has been determined in terms of H2S partial pressure, chloride concentration and temperature. The experiments were conducted on samples coming from both hot-rolled plates and long products, which cover a wide amount of stainless steel components for oil & gas exploitation.
Stress corrosion cracking under evaporative conditions is also a major concern in oil & gas production, storage, and processing. An innovative test method was used for evaluation of welded UNS S32202 susceptibility to atmospheric cracking in presence of chloride deposits.
The results of this study show that UNS S32202 can be a good candidate for various applications in the oil & gas industry. It can be an interesting material for subsea equipment, such as flowlines under mild H2S conditions, as well as for topside applications.