NACE MR0175/ISO 15156-2:2003 lists J55 tubing as acceptable for sour service without
temperature restriction in “SSC Region 3” as defined by Figure 1 of that standard. API 5CT does not
require hydrogen induced cracking (HIC) testing of J55 tubing and NACE MR0175/ISO 15156-2:2003
only states that the equipment user consider HIC or stepwise cracking (SWC) of flat-rolled carbon steel
products.
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A sample of electric welded API 5CT grade J55 casing obtained during a mill audit
nevertheless exhibited extensive HIC during testing in NACE Solution A at room temperature. HIC
occurred despite acceptable mechanical properties and chemistry, a mill quality plan, certification by
API and ISO, and favorable mill audit results. Susceptibility to HIC was primarily attributed to centerline
segregation and inhomogeneous microstructure of parent skelp. Unless a mill can demonstrate a
history of consistently producing high quality of API 5CT grade H, J, and K electric welded products,
HIC and/or SSC testing of these materials should be considered for sour service applications.
Keywords: hydrogen induced cracking, electric welded casing, centerline segregation