Failure analysis of the left waterwall tube of boiler furnace in the steam power plant based on thickness changes and pressure

Novi Sukma Drastiawati*, H. C. Kis Agustin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose – The purpose of this paper is to analyze the failure of the left waterwall tube of a boiler furnace in the steam power plant which led to cracks and rupture. Macro visual observation showed the rupture like a fish mouth with slag adhering at the outer surface of the tube. Magnetite as a protective layer was peeled off. Changes in the thickness were analyzed through dimensional measurement. In this research, an analysis to find the cause and determine the fracture mechanism is presented. Design/methodology/approach – A physical analysis was performed through visual observation of changes in the thickness. Micro visual testing with a metallography test provided the data required to measure the change of grain size. The mechanical analysis used Von Mises criteria and API 530 standard and provided the pressure limits data. Findings – The thickness of the tube decreased at the peak curvature of the tube. The smallest thickness at the peak curvature of the tube was 0.108 inches. The working pressure was 40.74 percent from permit limits with Von Mises calculations. The percentage of pressure calculated by the API standard was 48.42 percent from permit limits. Larger crystal grains occurred only in the nearby area of the oxide layer and at the end of the crack tip. It indicated that part of the inner surface had a relatively high temperature and plastic deformation occurred because of the pressure from inside the tube. Combining all these factors ruptured the tube at this location because the cross-section could not hold up the pressure. Originality/value – The analysis of this discussion focuses on the combined effect of those factors causing the ability to decrease stress being received. It restricts the tube from holding up the stress and furthermore it will generate fractures.

Original languageEnglish
Pages (from-to)539-549
Number of pages11
JournalMultidiscipline Modeling in Materials and Structures
Volume13
Issue number4
DOIs
Publication statusPublished - 9 Nov 2017

Keywords

  • API 530
  • Plastic deformation
  • Pressure
  • Thickness changes
  • Von Mises
  • Waterwall tube failure

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