Variation of Creep Properties in HP Steel by Influence of Temperature

Alessio, D.; González, Gabriel J.; Pirrone, V. Fernandez; Iurman, L.; Moro, L.

doi:10.1016/j.mspro.2012.06.014

Cited by 9 publications

(6 citation statements)

References 4 publications

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“…At higher temperatures, the G-phase dissolves and the Nb is incorporated in the M 23 C 6 carbide. Similar observations regarding the type and morphologies of various carbides in creep-exposed HP-Nb steels have been reported by Allesio et al [2] and Almeida et al [15]. Finally, the presence of NbC carbides and the corresponding absence of G-phase in the H5 condition in the Ti-containing material validated previous observations that Ti stabilizes the MC carbide and acts against the transformation of the MC carbides to the G-phase [11,17].…”

Section: Discussionsupporting

confidence: 90%

Section: Discussionsupporting

confidence: 87%

“…The current state-of-the-art is to use modified HP-alloys (25Cr-35Ni), with Nb and/or Ti additions. Niobium is added for the precipitation of NbC, which due to its thermal stability contributes to an increased creep resistance [1,2]. Centrifugal casting results in austenitic dendritic grains oriented in the radial direction from the inside diameter (ID) towards the outside diameter (OD) of the tube.…”

Section: Introductionmentioning

confidence: 99%

“…Premature failures of reformer tubes are frequently observed and are caused by various mechanisms such as creep, carburization, and thermal shock. Evaluation of creep damage in reformer tubes has been reported by several investigators, either after creep testing [2,4,5], after a certain operational time [6][7][8][9][10], or after premature tube rupture [11,12]. In addition, specific studies of microstructural evolution after long-term aging at high temperatures have been performed [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Aging Phenomena during In-Service Creep Exposure of Heat-Resistant Steels

Haidemenopoulos

Polychronopoulou

Zervaki

et al. 2019

Metals

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An investigation of aging phenomena during creep exposure has been conducted for HP-Nb cast reformer tubes for several exposure conditions. Aging was manifested by carbide precipitation, carbide coarsening, and carbide transformation. The transformation of primary M7C3 to the more stable M23C6 carbide takes place at high exposure temperature (910 °C and above). The primary MC carbides transform to the Ni-Nb silicide or G-phase during creep exposure. The presence of Ti in the steel prevented the transformation of MC carbides to the G-phase. Morphological changes like needle to globular transitions, rounding of carbide edges, and carbide coarsening take place during creep exposure. The room-temperature tensile elongation and ultimate tensile strength are significantly reduced during creep exposure. The above aging phenomena are precursors to creep damage.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Aging Phenomena during In-Service Creep Exposure of Heat-Resistant Steels

Haidemenopoulos

Polychronopoulou

Zervaki

et al. 2019

Metals

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“…Mientras que las aleaciones de niquel presentan una microestructura constituida por una matriz formada por una solución sólida fcc (fase γ) y un disperso de precipitados intermetálicos (fase γ´) que son los responsables de su gran resistencia. En particular el acero HP modificado, se utiliza ampliamente en las industrias petroquímicas de nuestra región, para construir los hornos de pirolisis porque presentan resistencia a la termofluencia gracias a la estabilidad de las fases que lo componen (Alessio D, 2012).…”

Section: Introductionunclassified

Estudio de las propiedades al creep en aceros termorresistentes

González

Moro²,

Iurman³

2020

AJEA

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Cuando los componentes de una planta industrial se encuentran sometidos a condiciones severas de temperatura y esfuerzos mecánicos, sufren una deformación plástica que continua a lo largo del tiempo. Este proceso, denominado termofluencia (creep), se presenta en industrias petroquímicas, plantas generadoras de energía y refinerías de petróleo, donde sus componentes son utilizados durante largos períodos de tiempo y expuestos a condiciones severas de servicio.El objetivo de esta tesis es estudiar el comportamiento al creep de aceros ferríticos (1Cr 0.5Mo, 2.25 Cr 1 Mo y 5Cr 0.5 Mo), y aleaciones base níquel ((Incoloy 800 (30 Ni – 20 Cr), Inconel 601 (60 Ni – 25 Cr) y aceros de la serie HP (25 Cr – 35 Ni) que poseen, alta resistencia termomecánica asociada a la microestructura interna de la matriz. Se analiza la variación de los parámetros característicos al creep, tales como la energía de activación y el coeficiente de tensión, relacionados con la velocidad de deformación, la tensión aplicada y la temperatura; simultáneamente se caracteriza la evolución microestructural, en las condiciones de temperatura y tiempo similares a los ensayos. En forma experimental, mediante ensayos de creep, se reproducirán condiciones de ensayo en el laboratorio, de características similares a las de operación en servicio. Las curvas experimentales obtenidas de esta forma, nos van a permitir conocer la variación de las propiedades físicas y mecánicas; estudiar los mecanismos responsables del fenómeno y describir parámetros que estén vinculados con la resistencia mecánica del material.

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