Dispersed-MnS Inclusion Pipeline Steel

Near 3× HE Resistance

Trace Mg treatment forms finely dispersed MnS-based complex inclusions that replace coarse CaS inclusions, greatly enhancing hydrogen embrittlement resistance of pipeline steel.

Zhiyi, Wang · Chen, Tianqi · Liu, Jing · Haocong, An · Zhong, Li · Liu, Chao · Huang, Feng · Liu, Zhiyong · Li, Xiaogang

Corrosion Science 2026

Specifications

HE susceptibility

{'zh': '21.3', 'en': '21.3'} %

HAGB fraction

{'zh': '45.1', 'en': '45.1'} %

Hydrogen segregation energy at MnS/matrix

{'zh': '-0.821', 'en': '-0.821'} eV

Potential difference variation

{'zh': '16', 'en': '16'} mV

Advantages

HE susceptibility halved

Trace Mg treatment reduces HE susceptibility from 44.0% to 21.3% by replacing coarse CaS with MnS-based inclusions that have lower hydrogen segregation energy.

Stronger interfacial hydrogen trapping

The MnS/matrix interface exhibits hydrogen segregation energy of −0.821 eV and potential difference variation of 16 mV, double that of CaS (8 mV), indicating stronger hydrogen trapping.

More high-angle boundaries

The fraction of high-angle grain boundaries increases from 38.9% to 45.1%, improving resistance to crack propagation.

Fine and dispersed inclusions

Finely sized (< 2 μm) and massively dispersed MnS and complex inclusions replace coarse CaS, avoiding local hydrogen accumulation.

Applications

• Pipeline Steel：For pipelines carrying sour gas or hydrogen, resisting hydrogen-induced cracking.
• Hydrogen-Resistant Materials：Reducing local hydrogen accumulation risk via inclusion modification.
• Hydrogen Storage and Transport：Enhancing steel durability in high-pressure hydrogen environments.