Effect of microstructure on hydrogen embrittlement sensitivity and failure mechanism of X52 pipeline steel

Bibliographic Details
Title: Effect of microstructure on hydrogen embrittlement sensitivity and failure mechanism of X52 pipeline steel
Authors: Qian Wu, Anfeng Yu, Yi Qin, Yuchen Wang, Weimin Zhao, Wenchen Wang
Source: Journal of Materials Research and Technology, Vol 35, Iss , Pp 5307-5321 (2025)
Publisher Information: Elsevier, 2025.
Publication Year: 2025
Collection: LCC:Mining engineering. Metallurgy
Subject Terms: Microstructure, Hydrogen embrittlement sensitivity, Failure mechanism, Pipeline steel, Mining engineering. Metallurgy, TN1-997
More Details: Hydrogen embrittlement (HE) susceptibility is intrinsically linked to the material's microstructural characteristics. This study systematically investigated API X52 pipeline steel through in-situ tensile testing under 6 MPa hydrogen pressure, complemented by microstructural characterization, fractographic analysis, and hydrogen microprint test (HMT). A comparative assessment of hydrogen embrittlement resistance was conducted between base metal and welded joints, particularly on microstructural influences on failure mechanisms. It was found that under a 6 MPa hydrogen environment, the hydrogen embrittlement sensitivity of the API X52 base metal selected in this article is higher than that of the welded joint. A gradient microstructural distribution was observed along the direction of the pipe wall thickness. The outer wall region predominantly consists of polygonal ferrite with a minor fraction of granular bainite. A progressive increase in bainitic phase fraction was detected toward the inner wall, ultimately transitioning to bainite structures. Secondary cracks appear on the tensile fracture surface of the base metal under a hydrogen pressure of 6 MPa. The cracks mainly originate from granular carbides and propagate along the grain boundaries. HMT analysis revealed preferential hydrogen segregation at the carbide or grain boundary. The precipitated carbides at grain boundaries play a significant role in hydrogen trapping, and the hydrogen accumulation at the interface between precipitated carbides and the matrix is the main reason for transgranular fracture. The tensile fracture of the welded joints in nitrogen and 6 MPa hydrogen environments was found in the softened zone of the heat-affected zone. The failure mode of the welded joint was mainly dominated by strength and had no hydrogen-induced failure characteristics.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 2238-7854
Relation: http://www.sciencedirect.com/science/article/pii/S2238785425003758; https://doaj.org/toc/2238-7854
DOI: 10.1016/j.jmrt.2025.02.128
Access URL: https://doaj.org/article/fdebfd98520348e7bf1eea1b88164267
Accession Number: edsdoj.fdebfd98520348e7bf1eea1b88164267
Database: Directory of Open Access Journals
More Details
ISSN:22387854
DOI:10.1016/j.jmrt.2025.02.128
Published in:Journal of Materials Research and Technology
Language:English