Performance of Pipeline Steels in Sour Service

Abstract

The demand for steel for the production of pipelines to transport gas and oil containing hydrogen sulphide prompted the development of steel that is resistant to hydrogen induced cracking (HIC).</jats:p> <jats:p>During the past two decades, combined research efforts in the areas of product and process metallurgy have made it possible to satisfy most of the main requirements for grades X-42 and X-60 microalloyed steel for mildly acidic (pH = 5) H2S environments. Building on the experience acquired in the area of microalloyed steel for a mildly acidic (pH ∼ 5) H2S environment, the industry launched a program to develop steel that would satisfy new requirements for H2S-resistant pipelines under NACE conditions (TM0177, pH∼3). In order to develop these steels, it was necessary to define qualitatively and quantitatively the specific effects on H2S resistance of the multiple intrinsic parameters of the product itself as well as those resulting from the process.</jats:p> <jats:p>In this paper, data will be presented that have made it possible to relate the HIC performance of steels to chemical content, inclusion levels and thermomechanical treatment parameters.