EFFECT OF REELING ON SULFIDE STRESS CORROSION CRACKING OF WELDED API5LX65 LINE PIPE

摘要

The effect of reeling on sulfide stress cracking (SSC) resistance of welded line pipe was investigated in two different environments, a modified NACE B environment and a fitness for service environment (pH = 5/pH_2S = 0.46psia). Micro hardness maps were performed to characterize the welds both in the as fabricated condition as well as in the strained and aged condition. The hardness values in all of the conditions, was less than 250VHN (in compliance with NACE requirements). Triplicate specimens were tested in the as fabricated, strained and aged intrados and extrados in both the environments. SSC resistance in a severely sour environment (pH = 3.5/lpsia H_2S) was affected by reeling with cracking observed in both the intrados and extrados samples. No cracking was observed in the as-fabricated welds. However, in a moderately sour environment (pH = 5/0.46psia H_2S) reeling did not have a detrimental effect on the SSC performance. No evidence of cracking on the as-fabricated, intrados, and extrados welds. In moderate sour service reeling doesn't appear to have a detrimental effect on the SSC behavior.