Steel with yield strengths below about 900 MPa are essentially immune to hydrogen embrittlement, and almost all pipeline steels have a yield strength below that value. However, same catastrophic failures of pipelines have been reported. Under mechanical stress these failures are due to the local formation of high-hardness martensite (hard spot) during cooling and from the presence of absorbed hydrogen developed under cathodic over-protection. This paper describes a photoelectrochemical, micrographic and fractographic study of the effect of an heat-affected zone (hard spot) on hydrogen permeation and the embrittlement of an API 5L STD X60 steel.
Effect of the heat-affected zones on hydrogen permeation and embrittlement of low-carbon steels
Maffi S;
1998
Abstract
Steel with yield strengths below about 900 MPa are essentially immune to hydrogen embrittlement, and almost all pipeline steels have a yield strength below that value. However, same catastrophic failures of pipelines have been reported. Under mechanical stress these failures are due to the local formation of high-hardness martensite (hard spot) during cooling and from the presence of absorbed hydrogen developed under cathodic over-protection. This paper describes a photoelectrochemical, micrographic and fractographic study of the effect of an heat-affected zone (hard spot) on hydrogen permeation and the embrittlement of an API 5L STD X60 steel.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
