| Partner: J.L.G Velazquez |
Ostatnie publikacje
| 1. | Entezari E.♦, Singh A.♦, Mousavisogolitappeh H., Velazquez J.♦, Szpunar J.♦, A cost-effective model for synergistic effects of microstructure and crystallographic texture on hydrogen-induced crack growth and corrosion rates in pipeline steels, Materials Characterization, ISSN: 1044-5803, DOI: 10.1016/j.matchar.2025.114917, Vol.223, No.114917, pp.1-23, 2025 Streszczenie: his study proposes a Cost-Effective model based on microstructure, crystallographic texture, and hydrogen (H) diffusion to evaluate H-damage in pipeline steels. H-crack growth and corrosion rates, measured using ultrasonic inspection and a Gamry electrochemical setup, were correlated with microstructure and texture. Results show that smaller ferrite grain size, lower density of co-incidence site lattice boundaries (CSLB), higher densities of geometrically necessary boundaries (GNB) and random high-angle grain boundaries (RHAGB), and higher overall stored energy (EAve) in texture fibers increase H-trap sites and reduce effective H-diffusivity, contributing to higher H-crack growth rates. Conversely, these same factors enhance corrosion resistance by improving passivation. Secondary phases have a detrimental effect on H-crack growth and corrosion resistance, varying with size, continuity, and volume fraction of phases. The proposed model, using hyperparameter tuning, quantifies the synergistic effects of microstructure, texture, and H-diffusion on H-damage and highlights the role of ferrite grain size in mitigating H-damage in pipeline steels. Finally, finite element (FE) analysis of grain structures provided supporting observations. Słowa kluczowe: H-crack growth rate, Corrosion rate, Microstructure, Crystallographic texture, Cost- effective model, Finite element stress analysis Afiliacje autorów:
|  | 100p. | |||||||||||||||||||||
| 2. | Entezari E.♦, Velazquez J.♦, Lopez D.♦, Zuniga M.♦, Mousavisogolitappeh H., Davani R.♦, Szpunar J.♦, An experimental and statistical study on the characteristics of non-metallic inclusions that serve as hydrogen-induced crack nucleation sites in pipeline steel, Engineering Failure Analysis, ISSN: 1350-6307, DOI: 10.1016/j.engfailanal.2023.107695, Vol.154, No.107695, pp.1-15, 2023 Streszczenie: This study consists of a statistical study to identify spatial distribution parameters of non-metallic inclusions (NMIs) at hydrogen-induced cracking (HIC) nucleation sites in both low-strength and high-strength steel pipes. The electrochemical cathodic charging method was used to induce HIC in pipeline steel plates, and the nucleation of the HIC was monitored using straight beam ultrasonic testing. Optical microscopy (OM) and scanning electron microscopy (SEM) were used to evaluate the shape, size, area fraction, and separation distance of NMIs. The hydrogen microprint technique (HMT), electron backscattered diffraction (EBSD) analysis, and finite element (FE) stress analysis were performed to characterize HIC nucleation sites. The findings showed that cubical and spinal NMIs, characterized by strong hydrogen trapping capacity due to high misfit strain and von Mises stress, are favored sites for HIC nucleation. The main finding of this study is that the shape and sharpness of NMIs are the factors that determine when NMIs will be a HIC nucleation site, rather than size, as generally accepted. Słowa kluczowe: Hydrogen-induced cracking, Statistical study, Non-metallic inclusions, Hydrogen microprint technique, Finite element stress analysis Afiliacje autorów:
| | 100p. |