The influence of operation of API 5L X67 steel and specimen notch orientation on the impact toughness

• DOI: 10.15407/pcmm2025.02.111
• Publication Date: 2025-05-02T10:05:12Z
• Authors: D. O. Demianchuk; O. T. Tsyrulnyk; ; P. R. Solovei; ; H. M. Nykyforchyn; ; О. І. Zvirko

The operational embrittlement based on the determination of the impact toughness KCV of longitudinal and transverse to the rolling direction specimens of API 5L X67 steel of the reserve pipes and operated for 34 years on the gas main pipeline was investigated. The influence of different orientations of the notch in the specimens relative to the rolling direction and the pipe axis was analyzed and a significant influence of this factor on the impact toughness was revealed, which is generally higher for specimens with a notch oriented in the short transversal direction. The sensitivity of KCV to operational degradation was the highest for tests of transverse specimens with a concentrator in the axial direction. Using macrofractographic analysis, a typical low-energy delamination along the rolling direction was observed.