Menu
Search
Filters
Close
Menu

51314-3794-Cracking of a Bi-Metallic Weld in HF Acid Service

Picture for Cracking of a Bi-Metallic Weld in HF Acid Service
Available for download
Product Number: 51314-3794-SG
ISBN: 3794 2014 CP
Author: Joyce Mancini
Publication Date: 2014
$0.00
$0.00
$0.00
A solid Monel nozzle welded into the carbon steel shell of a refinery HF acid settler failed due to H2 embrittlement cracking of the carbon steel along the bi-metallic weld fusion zone. This resulted in a thru-wall fracture opening up and propagating around the nozzle-to-shell weld on the vessel OD from the 12 o’clock to 6 o’clock position in a matter of hours. The metallurgical examination determined the root cause to be hydrogen induced stress cracking of carbon steel due to a combination of hard spots in the bi-metallic weld fusion zone galvanically-enhanced HF corrosion and corrosion product formation with operational stresses likely providing the final load element to propagate the thru-wall failure.Several design modifications were made to reduce the future risk of H2 embrittlement cracking coupled with inspection/monitoring enhancements to assure its future integrity. In addition inspection techniques were evaluated to ensure any future issues could reliably be detected.This paper reviews the causes of the failure the design modifications required to reduce the potential for future issues and the inspection methods identified that will allow for continued assurance of reliable service.  
A solid Monel nozzle welded into the carbon steel shell of a refinery HF acid settler failed due to H2 embrittlement cracking of the carbon steel along the bi-metallic weld fusion zone. This resulted in a thru-wall fracture opening up and propagating around the nozzle-to-shell weld on the vessel OD from the 12 o’clock to 6 o’clock position in a matter of hours. The metallurgical examination determined the root cause to be hydrogen induced stress cracking of carbon steel due to a combination of hard spots in the bi-metallic weld fusion zone galvanically-enhanced HF corrosion and corrosion product formation with operational stresses likely providing the final load element to propagate the thru-wall failure.Several design modifications were made to reduce the future risk of H2 embrittlement cracking coupled with inspection/monitoring enhancements to assure its future integrity. In addition inspection techniques were evaluated to ensure any future issues could reliably be detected.This paper reviews the causes of the failure the design modifications required to reduce the potential for future issues and the inspection methods identified that will allow for continued assurance of reliable service.  
Product tags
Also Purchased
Picture for 03651 Specification for Carbon Steel Materials
Available for download

03651 Specification for Carbon Steel Materials for Hydrofluoric Acid Alkylation Units

Product Number: 51300-03651-SG
ISBN: 03651 2003 CP
Author: Andy Gysbers, Hisham Hashim, Dannie Clarida, Gregmar Chirinos, Dr. John Marsh, Dr. Jim Palmer
Publication Date: 2003
$20.00

 Joint Industry Project “Materials Specification for HF Alkylation Plant” to develop test and corrosion rate measurement procedures for materials in HF environments and to develop a carbon steel materials specification w.r.t levels of residual elements and carbon in steels for HF alkylation equipment.
Picture for 99382 Characterization of Corrosion Resistant
Available for download

99382 Characterization of Corrosion Resistant Materials in Low and High Temperature HF Environments

Product Number: 51300-99382-SG
ISBN: 99382 1999 CP
Author: J. R. Crum, G. D. Smith, M. J. McNallan and S. Hirnyj
$20.00
Picture for 00518 MATERIALS BEHAVIOR IN HIGH TEMPERATURE
Available for download

00518 MATERIALS BEHAVIOR IN HIGH TEMPERATURE HF-CONTAINING ENVIRONMENTS

Product Number: 51300-00518-SG
ISBN: 00518 2000 CP
Author: John J. Barnes
$20.00
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