Influence of hydrogen fugacity on the fracture toughness and fracture mechanism of a X65 natural gas transmission pipeline steel

Abstract:

The influence of hydrogen on the fracture of X65 was studied. The fracture toughness in air was 369 MPa√m. The ASTM-valid fracture toughness with cathodic hydrogen charging was lower but was similar for these charging conditions 189 MPa√m and 181 MPa√m at 9 mA/cm²; 192 MPa√m and 179 MPa√m at 16 mA/cm²; and 177 MPa√m at 25 mA/cm²; even though the fractography changed from (i) ductile fracture by microvoid coalescence in air and at 9 mA/cm² to (ii) more brittle fracture for hydrogen charging at 16 mA/cm² and 25 mA/cm², with flat facets and secondary cracks, which increased with increasing current density.

Año de publicación:

2024

Keywords:

• Brittle fracture mechanism
• Cathodic hydrogen charging
• Fracture toughness
• hydrogen embrittlement
• pipeline steel
• Plastic fracture mechanism
• Stable crack growth
• STEEL

Fuente:

scopus