In this study a total of fourteen alloys tlom the groups of martensitic (MSS), precipitation hardened (PHSS), and duplex (DSS) stairdess steals were exposed to simulated petroleum production environments containing H2S, CO2, chloride and bicarbonate to produce a range of conditions. The particular focus of this study was the documentation of the efects of environmental and metallurgical variables on the resistance to stress corrosion cracking (SCC) and sulfide stress cracking (SSC) of these materirds. Slow strain teats were also conducted in order to obtain additional information. The SCC/SSC behavior of stairdeas steel alloys was observed to be significantly different for conditions resulting in pH < 4.0 than for those even pH > 4.0. But Tered environments producing pH greater than 4.0 tended to be considerably less severe tlom the standpoint of cracking In butTeredsolutions, the environmental limits for MSS and PHSS materials were 10,000 ppm C and 6.9 kPa (1,0 psia) H2S, The satleuse limits for coldworked DSS materials were 100,000 ppm Cl- and 6,9 kPa (1,0 psia) H2S under but Tered conditions. The annealed DSS were not susceptiblefor SCC at 100,000 ppm Cl-and up to 68.9 kPa (10 psia) H2Sunder unbutlkred conditions baaed on 30 day exposure data. The pH of the test environments had leas of an effect with increasing alloy content. The tested alloys exhibited the general trend of increasing general corrosion with increasing temperature. However, the MSS alloys and some of the DSS alloys exhibited increased srrweptibtity to locahxl comosionat 93 C (200 F) than at 204 C (400 F) due to the transitions horn passive to active behavior or from varying passive states (Le. oxide to sulfide).
Keywords: rnarterrsitic,precipitation hardened, duplex stress corrosion cracking, sulphide stress cracking, alow strain rate, localized corrosion