Il presente lavoro di tesi si propone di studiare e monitorare l’infragilimento da parte dell’idr... more Il presente lavoro di tesi si propone di studiare e monitorare l’infragilimento da parte dell’idrogeno, negli acciai che si trovano a contatto con ambienti tipici del settore petrolchimico. Molte apparecchiature e tubazioni in acciaio utilizzate per la lavorazione ed il trasporto di idrocarburi si trovano ad operare in ambienti caratterizzati dalla presenza di acido solfidrico e fase acquosa, noto anche come ambiente sour. Queste condizioni di servizio possono essere molto deleterie, in quanto la presenza di solfuri può dar luogo o a Sulfide Stress Cracking oppure a catalizzare la penetrazione dell’idrogeno nella matrice metallica. Tutto ciò può comportare l’alterazione delle proprietà meccaniche del materiale e l’instaurarsi di una serie di meccanismi di danneggiamento, fino ad arrivare al cedimento strutturale dell’apparecchiatura. Per riprodurre ambienti critici sour è stata valutata la possibilità di utilizzare tiosolfato di sodio per condurre prove alternative alle prove NACE T...
The work is aimed at studing the influence of manufacturing parameters on enamelling quality in o... more The work is aimed at studing the influence of manufacturing parameters on enamelling quality in order to prevent fishscale occurrence. The research is a collaboration between Letomec srl and Electrolux Italia spA and it was conducted on steel samples representative of the materials employed in Electrolux products. The work involved experimental activities (electrochemical permeation, hydrogen content measurement and metallographic examinations) to evaluate the properties of the steel significant for the fishscale resistance. Fishscale susceptibility was investigated considering enamelling baking temperature, dew point of furnace, steel quality and the type of enamel.
A 16Cr5NiMo supermartensitic stainless steel was subjected to different tempering treatments and ... more A 16Cr5NiMo supermartensitic stainless steel was subjected to different tempering treatments and analyzed by means of permeation tests and slow strain rate tests to investigate the effect of different amounts of retained austenite on its hydrogen embrittlement susceptibility. The 16Cr5NiMo steel class is characterized by a very low carbon content. It is the new variant of 13Cr4Ni. These steels are used in many applications, for example, compressors for sour environments, offshore piping, naval propellers, aircraft components and subsea applications. The typical microstructure is a soft-tempered martensite very close to a body-centered cubic, with a retained austenite fraction and limited δ ferrite phase. Supermartensitic stainless steels have high mechanical properties, together with good weldability and corrosion resistance. The amount of retained austenite is useful to increase low temperature toughness and stress corrosion cracking resistance. Experimental techniques allowed us t...
Corrosion is evaluated to be one of the most important cause for pipeline failures. Given the ser... more Corrosion is evaluated to be one of the most important cause for pipeline failures. Given the serious consequences of these events in terms of human safety, environmental preservation and cost saving, it is evident that on-field corrosion control could have a fundamental role. The aim of the present work was to meet this need with preliminary feasibility study to develop a test procedure, characterized at the same time by non-invasive approach and scientific rigor, to evaluate the possibility of on-line monitoring and assess the integrity of a pipeline during its operation. The experimental campaign was performed on a HSLA Steel X60, characterized by a ferritic microstructure with fine grains and ultimate tensile strength equal to 520MPa. The hydrogen interaction with steel was investigated by means of an advanced equipment based on an innovative high sensitivity hydrogen gas sensor. The following types of investigations were carried out [1]: - Various permeation tests were performe...
The problem of hydrogen embrittlement in ultra-high-strength steels is well known. In this study,... more The problem of hydrogen embrittlement in ultra-high-strength steels is well known. In this study, slow strain rate, four-point bending, and permeation tests were performed with the aim of characterizing innovative materials with an ultimate tensile strength higher than 1000 MPa. Hydrogen uptake, in the case of automotive components, can take place in many phases of the manufacturing process: during hot stamping, due to the presence of moisture in the furnace atmosphere, high-temperature dissociation giving rise to atomic hydrogen, or also during electrochemical treatments such as cataphoresis. Moreover, possible corrosive phenomena could be a source of hydrogen during an automobile’s life. This series of tests was performed here in order to characterize two press-hardened steels (PHS)—USIBOR 1500® and USIBOR 2000®—to establish a correlation between ultimate mechanical properties and critical hydrogen concentration.
Il presente lavoro di tesi si propone di studiare e monitorare l’infragilimento da parte dell’idr... more Il presente lavoro di tesi si propone di studiare e monitorare l’infragilimento da parte dell’idrogeno, negli acciai che si trovano a contatto con ambienti tipici del settore petrolchimico. Molte apparecchiature e tubazioni in acciaio utilizzate per la lavorazione ed il trasporto di idrocarburi si trovano ad operare in ambienti caratterizzati dalla presenza di acido solfidrico e fase acquosa, noto anche come ambiente sour. Queste condizioni di servizio possono essere molto deleterie, in quanto la presenza di solfuri può dar luogo o a Sulfide Stress Cracking oppure a catalizzare la penetrazione dell’idrogeno nella matrice metallica. Tutto ciò può comportare l’alterazione delle proprietà meccaniche del materiale e l’instaurarsi di una serie di meccanismi di danneggiamento, fino ad arrivare al cedimento strutturale dell’apparecchiatura. Per riprodurre ambienti critici sour è stata valutata la possibilità di utilizzare tiosolfato di sodio per condurre prove alternative alle prove NACE T...
The work is aimed at studing the influence of manufacturing parameters on enamelling quality in o... more The work is aimed at studing the influence of manufacturing parameters on enamelling quality in order to prevent fishscale occurrence. The research is a collaboration between Letomec srl and Electrolux Italia spA and it was conducted on steel samples representative of the materials employed in Electrolux products. The work involved experimental activities (electrochemical permeation, hydrogen content measurement and metallographic examinations) to evaluate the properties of the steel significant for the fishscale resistance. Fishscale susceptibility was investigated considering enamelling baking temperature, dew point of furnace, steel quality and the type of enamel.
A 16Cr5NiMo supermartensitic stainless steel was subjected to different tempering treatments and ... more A 16Cr5NiMo supermartensitic stainless steel was subjected to different tempering treatments and analyzed by means of permeation tests and slow strain rate tests to investigate the effect of different amounts of retained austenite on its hydrogen embrittlement susceptibility. The 16Cr5NiMo steel class is characterized by a very low carbon content. It is the new variant of 13Cr4Ni. These steels are used in many applications, for example, compressors for sour environments, offshore piping, naval propellers, aircraft components and subsea applications. The typical microstructure is a soft-tempered martensite very close to a body-centered cubic, with a retained austenite fraction and limited δ ferrite phase. Supermartensitic stainless steels have high mechanical properties, together with good weldability and corrosion resistance. The amount of retained austenite is useful to increase low temperature toughness and stress corrosion cracking resistance. Experimental techniques allowed us t...
Corrosion is evaluated to be one of the most important cause for pipeline failures. Given the ser... more Corrosion is evaluated to be one of the most important cause for pipeline failures. Given the serious consequences of these events in terms of human safety, environmental preservation and cost saving, it is evident that on-field corrosion control could have a fundamental role. The aim of the present work was to meet this need with preliminary feasibility study to develop a test procedure, characterized at the same time by non-invasive approach and scientific rigor, to evaluate the possibility of on-line monitoring and assess the integrity of a pipeline during its operation. The experimental campaign was performed on a HSLA Steel X60, characterized by a ferritic microstructure with fine grains and ultimate tensile strength equal to 520MPa. The hydrogen interaction with steel was investigated by means of an advanced equipment based on an innovative high sensitivity hydrogen gas sensor. The following types of investigations were carried out [1]: - Various permeation tests were performe...
The problem of hydrogen embrittlement in ultra-high-strength steels is well known. In this study,... more The problem of hydrogen embrittlement in ultra-high-strength steels is well known. In this study, slow strain rate, four-point bending, and permeation tests were performed with the aim of characterizing innovative materials with an ultimate tensile strength higher than 1000 MPa. Hydrogen uptake, in the case of automotive components, can take place in many phases of the manufacturing process: during hot stamping, due to the presence of moisture in the furnace atmosphere, high-temperature dissociation giving rise to atomic hydrogen, or also during electrochemical treatments such as cataphoresis. Moreover, possible corrosive phenomena could be a source of hydrogen during an automobile’s life. This series of tests was performed here in order to characterize two press-hardened steels (PHS)—USIBOR 1500® and USIBOR 2000®—to establish a correlation between ultimate mechanical properties and critical hydrogen concentration.
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Papers by Serena Corsinovi