Effect of severe operation conditions on the degradation state of radiant coils in pyrolysis furnaces

Santos, Milene; Guedes, M.; Baptista, R.; Infante, V.; Cláudio, R.A.

doi:10.1016/j.engfailanal.2015.02.010

Cited by 11 publications

(1 citation statement)

References 17 publications

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“…The more heavy an atom is, the more a BSE signal can be generated, giving results in a brighter contrast. Therefore, the BSE is used to detect contrasts between areas with different elemental compositions [19,20]. Figure 4a,b shows the backscattered electrons images (BEI) of Specimen No.…”

Section: Materials Verificationmentioning

confidence: 99%

The Study of Heat Treatment Effects on Chromium Carbide Precipitation of 35Cr-45Ni-Nb Alloy for Repairing Furnace Tubes

Srisuwan

Eidhed

Kreatsereekul

et al. 2016

Metals

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This paper presents a specific kind of failure in ethylene pyrolysis furnace tubes. It considers the case in which the tubes made of 35Cr-45Ni-Nb high temperature alloy failed to carburization, causing creep damage. The investigation found that used tubes became difficult to weld repair due to internal carburized layers of the tube. The microstructure and geochemical component of crystallized carbide at grain boundary of tube specimens were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) with back-scattered electrons mode (BSE), and energy dispersive X-ray spectroscopy (EDS). Micro-hardness tests was performed to determine the hardness of the matrix and the compounds of new and used tube material. The testing result indicated that used tubes exhibited a higher hardness and higher degree of carburization compared to those of new tubes. The microstructure of used tubes also revealed coarse chromium carbide precipitation and a continuous carbide lattice at austenite grain boundaries. However, thermal heat treatment applied for developing tube weld repair could result in dissolving or breaking up chromium carbide with a decrease in hardness value. This procedure is recommended to improve the weldability of the 35Cr-45Ni-Nb used tubes alloy.

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Section: Materials Verificationmentioning

confidence: 99%