کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
773876 | 1462985 | 2014 | 7 صفحه PDF | دانلود رایگان |
• We investigate the failure of 35%Cr–45%Ni furnace coils coated with anti-coking film.
• Localized blister formation and oxidative cracking was observed on the coils.
• The results indicate the presence of inherent casting defects.
• Segregation of cerium at the defect site is proposed as a plausible damage mechanism.
This paper presents a specific kind of failure in ethylene cracking coils coated with anti-coking film. It investigates a case in which the coils made of 35Cr 45Ni high temperature alloy failed within two years of operation. The damage occurred due to heavy oxidation in localized regions of the coil resulting in the formation of blisters, which eventually failed by cracking. The mechanism involved was determined by studying the oxidized samples under a scanning electron microscope with an energy dispersive system and is attributed to the presence of rare earth metals in the anti-coking film and inherent casting defects in the base alloy. The cerium present in the anti-coking film diffused preferentially to a defect site in the parent alloy thereby resulting in its segregation which further led to embrittlement.
Journal: Engineering Failure Analysis - Volume 39, April 2014, Pages 181–187