# Influence of Calcareous Deposits on Hydrogen Embrittlement Susceptibility of Q460 Steel

## TL;DR

This study shows that calcareous deposits formed under specific cathodic potentials can reduce hydrogen embrittlement in Q460 steel used in marine environments.

## Contribution

The study reveals how calcareous deposits' structure and composition influence hydrogen embrittlement in Q460 steel under cathodic protection.

## Key findings

- Q460 steel showed the least hydrogen embrittlement when covered with calcareous deposits formed under −1.1 VSCE.
- The deposits' layered structure inhibits hydrogen entry, reducing embrittlement susceptibility.
- Sustained deposition reactions during testing in seawater further decrease hydrogen embrittlement.

## Abstract

Cathodic protection is widely used to protect structural steel from corrosion in marine environments. However, an inappropriate cathodic potential may lead to hydrogen embrittlement (HE). Therefore, this study investigates the relationship between cathodic protection potential, structure and composition of calcareous deposits, and hydrogen embrittlement susceptibility of Q460 steel. The slow strain rate test results and fracture analysis reveal that Q460 steel had the smallest HE susceptibility when covered with the calcareous deposits formed under −1.1 VSCE. The deposits have a relatively thin calcium-rich inner layer and a condensed magnesium-rich outer layer, which can significantly inhibit hydrogen entry. A sustained deposition reaction during slow strain rate testing (SSRT) in artificial seawater can also decrease the HE susceptibility of Q460 steel.