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A Review Of Fit-For-Purpose Sour Tests Of Low Alloy Steels: Effects Of Buffer Chemistry And Purge Gas Composition

Product Number: 51321-16578-SG
Author: Brian Chambers / Manuel Gonzalez
Publication Date: 2021
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Oil country tubular goods (OCTG) are routinely evaluated for sulfide stress cracking (SSC) resistance. Historically, most qualifications relied on full sour, i.e. 1 bar H2S, to assure sour grades of OCTG for service in the field. Over the past two decades, it has become more routine to evaluate SSC resistance of OCTG, often higher strength grades, using fit-for-purpose (FFP) conditions. The practice of FFP testing of low alloy steels has evolved from methods outlined in EFC(1) 16 to NACE(2) (MR0175/ISO315156 - TM0177) and API(4) 5CT. This paper reviews the original practices outlined in EFC 16 and the current range of practices used in industry with regards to the technical validity and conservatism of evaluations performed.

Key words: H2S, sour, sulfide stress cracking, acetate buffer, OCTG, MR0175, TM0177, DCB

Oil country tubular goods (OCTG) are routinely evaluated for sulfide stress cracking (SSC) resistance. Historically, most qualifications relied on full sour, i.e. 1 bar H2S, to assure sour grades of OCTG for service in the field. Over the past two decades, it has become more routine to evaluate SSC resistance of OCTG, often higher strength grades, using fit-for-purpose (FFP) conditions. The practice of FFP testing of low alloy steels has evolved from methods outlined in EFC(1) 16 to NACE(2) (MR0175/ISO315156 - TM0177) and API(4) 5CT. This paper reviews the original practices outlined in EFC 16 and the current range of practices used in industry with regards to the technical validity and conservatism of evaluations performed.

Key words: H2S, sour, sulfide stress cracking, acetate buffer, OCTG, MR0175, TM0177, DCB

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