Menu
Search
Filters
Close
Menu

Stress-Assisted Corrosion Of A Superheater Tube: The Role Of Thermal Fatigue Cracking And Crevice Corrosion In The Failure Mechanism

Picture for Stress-Assisted Corrosion Of A Superheater Tube: The Role Of Thermal Fatigue Cracking And Crevice Corrosion In The Failure Mechanism
Available for download
Product Number: 51321-16530-SG
Author: Ewa Labuda/ W.B.A. (Sandy) Sharp
Publication Date: 2021
$0.00
$20.00
$20.00

This paper discusses the results of a failure examination of superheater tubes from a boiler. The superheater tubes failed along steamside fissures associated with external surface welds attaching finger bars to adjacent tubes. The morphologies of the fissures were consistent with stress-assisted corrosion (SAC). In addition, cracks typical of thermal fatigue were present on some ID surfaces and at the tips of some fissures. The elemental compositions of corrosion products within the wide SAC fissures, determined using Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray Spectroscopy (EDXS), support the possibility that crevice conditions led to accelerated corrosion during cool down periods, resulting in pit-like areas along the fissures. Failed and unfailed superheater tubes were examined using standard metallographic techniques. The results were used to develop a theory of the role of thermal fatigue cracking and crevice corrosion in SAC fissure initiation on the steamside surfaces of the superheater tubes and propagation through the tube walls.

Key words: stress-assisted corrosion, superheater tubes, crevice corrosion, thermal fatigue, welded attachments

This paper discusses the results of a failure examination of superheater tubes from a boiler. The superheater tubes failed along steamside fissures associated with external surface welds attaching finger bars to adjacent tubes. The morphologies of the fissures were consistent with stress-assisted corrosion (SAC). In addition, cracks typical of thermal fatigue were present on some ID surfaces and at the tips of some fissures. The elemental compositions of corrosion products within the wide SAC fissures, determined using Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray Spectroscopy (EDXS), support the possibility that crevice conditions led to accelerated corrosion during cool down periods, resulting in pit-like areas along the fissures. Failed and unfailed superheater tubes were examined using standard metallographic techniques. The results were used to develop a theory of the role of thermal fatigue cracking and crevice corrosion in SAC fissure initiation on the steamside surfaces of the superheater tubes and propagation through the tube walls.

Key words: stress-assisted corrosion, superheater tubes, crevice corrosion, thermal fatigue, welded attachments

Product tags
Also Purchased
Picture for 08458 Thermal Fatigue in a De-Superheater Induced by Thermal Loads
Available for download

08458 Thermal Fatigue in a De-Superheater Induced by Thermal Loads

Product Number: 51300-08458-SG
ISBN: 08458 2008 CP
Author: Bakheet Al-Yami
Publication Date: 2008
$20.00
Picture for 11151 Research for Creep Damage by Steam Oxidation
Available for download

11151 Research for Creep Damage by Steam Oxidation Scale of 9Cr Boiler Tubes after Long Time Service

Product Number: 51300-11151-SG
ISBN: 2011 11151 CP
Author: Hiroyasu Matsuda, Masahiko Takehara, Koji Kawano, Shigemitsu Kihara, Kouichi Yagi, Daisuke Horikoshi
Publication Date: 2011
$20.00
Picture for The Application of Ceramic Coatings to Extend Radiant Tube Life in Process Heaters and Improve Operational Efficiency with Cost Benefit Analysis
Available for download

The Application of Ceramic Coatings to Extend Radiant Tube Life in Process Heaters and Improve Operational Efficiency with Cost Benefit Analysis

Product Number: MPWT19-14438
Author: John Bacon, Johannes Poth and Iain Hall
Publication Date: 2019
$0.00

Ceramic coatings technologies are an effective surface engineering tool in the management of heat flux on metal surfaces. Thin ceramic coatings can be employed to either increase or decrease heat transfer on metal surfaces by modulation of emissivity. While this characteristic is relatively easily impressed on a surface, long term coating sustainability and oxidation protection of the underlying metal is not readily achieved. This presentation provides a technical data-based introduction to the function, performance, testing, and installation of ceramic coatings on two key pieces of refining equipment.
• Process heaters are critical production assets for the downstream hydrocarbon processing industries such as refineries and petrochemical plants. The efficient operation of these units is vital to plant productivity since they consume large amounts of energy to provide the required heat for the process. They may also bottleneck feed throughout due to heat transfer limits. Scaling and hot spots in the radiant tube section can cause local coking and premature material failure. Improvements in operating efficiency and reliability can yield significant cost benefits and a fast return on investment. Additionally, radiant transfer properties of existing refractory systems can be improved, increasing process efficiencies. Know ceramic performance metrics can be used to predictively model performance improvement. • Flare tips routinely suffer from material overheat, creep and oxidation. Ceramic systems are employed to mitigate these, through the installation of both low emissivity and low conductive heat transfer materials. This paper and case study discusses how different ceramic systems can be used in the management of heat transfer, the protection of surfaces from corrosion, and provide insight into the less intuitive mode by which heat transfer can be promoted.
Categories
Industry
Recently viewed
Popular tags
View all

Association for Materials Protection and Performance

© AMPP All Rights Reserved.
Membership Terms of Content Use
Contact Customer Support