It has been known that the microstructure of high strength steels can influence the hydrogen absorption, thus the sulfide stress cracking (SSC) resistance of the material. Recently, 125 ksi grade casing materials have been developed that have good SSC resistance in mild sour environments. However, the relationship between these materials’ microstructure and their SSC resistance has not been well understood.

In this investigation, a proprietary 125 ksi grade casing material with varying wall thickness, yield strength and hardness were used. The internal strain of the material after tempering was measured using X-ray diffraction technique. The prior austenite grain size of these materials was characterized using electron backscattered diffraction (EBSD) technique. Additional microstructural factors of these materials were investigated using transmission electron microscopy (TEM), including the precipitate shape, size, and distribution. A fundamental understanding of the SSC resistance of this 125 ksi grade casing material was thus developed by correlating the evaluated steel microstructural features with the measured KISSC values of these mateirals.

Subject
X-ray diffraction, Materials, Dislocation, Microstructure, Precipitates, Transmission electron microscopy, Density, Wall thickness, Steel, Sulfide stress cracking, Hardness, Martensite, Samples
Keywords:
sulfide stress cracking, thermal desorption spectroscopy, transmission electron microscopy, electron backscattered diffraction, X-ray Diffraction
© 2014 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2014
Association for Materials Protection and Performance (AMPP)
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