This is Part I of a two-part series intended to narrate the "lost" history leading up to the publication of the first Material Requirement (MR 0175) standard prepared by NACE (now AMPP) and its subsequent auxiliary standards. Part I covers field observations and describe the metallurgical issues the that were being investigated in support of NACE T-1B and 1F committees to develop a sour service materials standard. Part II focuses on the rationale behind the use of accelerated laboratory test procedures and their development used for accelerated testing to differentiate metallurgical behavior in sour environments at near atmospheric pressure. The original SSC test methodologies would later be codified as a Test Method in NACE TM 0177 (1977).
A review of the historical events culminating in NACE MR 0175 will provide a technical basis for the Rockwell C 22 (HRC 22) hardness limit for carbon and low alloy steels, information on the 1%Ni restriction, and heat treatment requirements. By recalling the origins of the MR0175 standard, these papers will also provide justification for their continued existence when designing modern, oil and gas wells and flowlines. As the oil and gas industry continues to innovate and mature, it is imperative to maintain knowledge of the origins of the NACE MR 0175 standard and its intended purpose.
This is Part I of a two-part series intended to provide background and a rational justification or supporting rationale for requirements leading to the development and publication of NACE(1) MR 0175 and ISO(2) 15156. Part I focuses on some of the metallurgical and processing requirements; specifically, Rockwell C 22 scale (HRC) limit, the various acceptable heat treatments and the 1wt% Ni limit for carbon and low alloy steels to minimize the threat of sulfide stress cracking (SSC) in H2S containing environments. Part II describes the testing and rationale behind the use of accelerated laboratory test procedures and their development to differentiate metallurgical behavior in sour environments 1. This series does not cover all the background and rationale for all the requirements that have become part of NACE MR 0175 and ISO 15156, only the aforementioned.