Browsing by Author "Gamboa, E"

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    The effect of the crystallographic texture on intergranular stress corrosion crack paths
    (Elsevier, 2014-11) Lavigne, O; Gamboa, E; Luzin, V; Law, M; Giuliani, M; Costin, W
    Intergranular stress corrosion cracking (IGSCC) crack paths usually travel perpendicular to the applied load direction. Some instances of crack paths propagating in directions away from the perpendicular have been observed in low carbon steels. This study shows that the crystallographic texture is a critical factor that drives the IGSCC crack path. Residual shear strain induced by shear texture (induced by rolling processes) explains the inclination of the cracks at a certain depth and the continuous propagation of the cracks along the transverse directions. The residual strains coming from the manufacturing processes determine the crack propagation paths. © 2014, Elsevier B.V.
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    High-pH inclined stress corrosion cracking in Australian and Canadian gas pipeline X65 steels
    (Taylor & Francis, 2016-05-02) Lavigne, O; Gamboa, E; Griggs, J; Luzin, V; Law, M; Roccisano, A
    High-pH stress corrosion cracking is a form of environmental degradation of gas pipeline steels. The crack path is intergranular by nature and typically perpendicular to the maximum applied (hoop) stress (i.e. perpendicular to the pipe outer surface). Some unusual instances of cracks have been observed in Canadian and Australian X65 pipes, where cracks grow away from the perpendicular for considerable distances. This paper presents a comparative study in terms of crack morphology, mechanical properties and crystallographic texture for these Australian and Canadian pipe steels. It is shown that the crack morphologies are quite similar, the main difference being the angle at which the cracks propagate into the material. This difference could be explained by the different through-wall texture and grain aspect ratio measured in the two materials. The interdependency of crack tip plasticity, crack tip electrochemistry and anisotropy in microstructural texture seems to heavily affect the resulting inclined crack path. © 2016 Taylor & Francis
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    An investigation of residual stress, hardness, and texture on stress corrosion cracking in a gas pipeline
    (Trans Tech Publication Ltd, 2014-02) Law, M; Luzin, V; Linton, V; Gamboa, E
    Stress Corrosion Cracking (SCC) may be a serious problem in gas pipelines. This work studies the hardness and residual stress profiles in two nominally identical sections of adjacent pipe with similar environment and coating, one of which was affected by detectable SCC and the other that was not. The results show changes in texture, residual stress, plastic strain, and hardness at the pipe surface which may be responsible for the altered susceptibility to SCC. © 2014, Trans Tech Publications.
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    Microstructural and mechanical factors influencing high pH stress corrosion cracking susceptibility of low carbon line pipe steel
    (Elsevier, 2014-10) Lavigne, O; Gamboa, E; Costin, W; Law, M; Luzin, V; Linton, V
    Several adjacent gas pipe sections were obtained from the field. These pipe sections had nominally identical manufacturing, construction, coating and operational conditions. Some sections were unaffected by stress corrosion cracking (SCC), whereas surrounding sections were affected by SCC. Slight differences in mechanical and microstructural properties were found between the two types of section. Residual stress/strain and hardness close to the outer surface of the pipes and high angle boundary fraction values were lower for the non-cracked pipe sections. Predominant 〈1 1 0〉//ND texture was also found at the outer surface of the non-cracked pipe sections. These characteristics lead to a lower crack growth rate in laboratory SCC experiments. These features being mainly a result of the line pipe steel manufacturing operations, appropriate metallurgical processes leading to low residual stress (6.2%YS), relatively low fraction of high angle boundaries (about 0.75) and predominant {1 1 0}〈1 1 0〉 texture in the material (or in the near surface) are expected to greatly improve the stress corrosion cracking resistance of line pipe steels on the field. © 2014, Elsevier Ltd.