The metallurgical characteristics of the damage observed in both service and laboratory test samples indicate that creep rupture is the dominant failure mode for Dissimilar Metal Welds (DMW) in some high temperature service conditions. However, it has also been observed that temperature cycling contributes significantly to damage and can cause failure even when primary stress levels are relatively low. Therefore, a creep-fatigue assessment procedure is required as part of a remaining life calculation. API 579-1/ASME FFS-1 2007 Fitness-For-Service standard includes a compendium of consensus methods for reliable assessment of the structural integrity of equipment containing identified flaws or damage. Part 10 of this document includes a method for protection against failure from creep-fatigue. In the assessment of DMW, a creep-fatigue interaction equation is provided to evaluate damage caused by thermal mismatch, sustained primary stresses, and cyclic secondary loads. In this work, alternative methods based on the ductility exhaustion with creep-fatigue interaction R5 V2/3 and R5 V6 are compared to the API 579-1/ASME FFS-1 standard method. The validity of an elastic FEA with linear material behavior is evaluated based on comparing results from FEA with nonlinear material behavior. A 2.25Cr 1Mo to SS 347 dissimilar joint welded with alloy 625 in a hydroprocessing heat exchanger nozzle joint was selected for the analysis. A Finite Element (FEA) model is used to estimate the sustained and cyclic primary and secondary stresses and strains for this weld. The model includes details of the geometry, material properties, boundary conditions, and loads. The results from the FEA are post-processed using the fatigue methods described above. Lastly, a sensitivity study based on operating temperature is performed. The results of this work indicate that the predictions of the number of cycles and time in service to crack initiation and creep failure are not significantly different between various methods. However, the results of the R5 V2/3 method using linear elastic FEA become invalid at higher temperatures because of significant stress redistribution. The temperature sensitivity analysis clearly showed that the life of the weld is strongly influenced by the service temperature for this type of joint.
Skip Nav Destination
ASME 2011 Pressure Vessels and Piping Conference
July 17–21, 2011
Baltimore, Maryland, USA
Conference Sponsors:
- Pressure Vessels and Piping Division
ISBN:
978-0-7918-4453-3
PROCEEDINGS PAPER
Comparison of Creep-Fatigue Fitness for Service Assessment Methods for Ferritic-Austenitic Dissimilar Welds Available to Purchase
Jorge A. Penso,
Jorge A. Penso
Shell Global Solutions (US), Inc., Houston, TX
Search for other works by this author on:
Radwan Hazime,
Radwan Hazime
Safe Technology (U.S.) Limited, Dearborn, MI
Search for other works by this author on:
Stephen Nungesser,
Stephen Nungesser
The Ohio State University, Columbus, OH
Search for other works by this author on:
Avraham Benatar
Avraham Benatar
The Ohio State University, Columbus, OH
Search for other works by this author on:
Jorge A. Penso
Shell Global Solutions (US), Inc., Houston, TX
Radwan Hazime
Safe Technology (U.S.) Limited, Dearborn, MI
Stephen Nungesser
The Ohio State University, Columbus, OH
Avraham Benatar
The Ohio State University, Columbus, OH
Paper No:
PVP2011-57280, pp. 739-747; 9 pages
Published Online:
May 21, 2012
Citation
Penso, JA, Hazime, R, Nungesser, S, & Benatar, A. "Comparison of Creep-Fatigue Fitness for Service Assessment Methods for Ferritic-Austenitic Dissimilar Welds." Proceedings of the ASME 2011 Pressure Vessels and Piping Conference. Volume 3: Design and Analysis. Baltimore, Maryland, USA. July 17–21, 2011. pp. 739-747. ASME. https://doi.org/10.1115/PVP2011-57280
Download citation file:
45
Views
Related Proceedings Papers
Related Articles
An Evaluation of Creep-Fatigue Damage for the Prototype Process Heat Exchanger of the NHDD Plant
J. Pressure Vessel Technol (October,2011)
Performance of Dissimilar Welds in Service
J. Pressure Vessel Technol (August,1985)
Failure Investigation of a Low Chrome Long-Seam Weld in a
High-Temperature Refinery Piping System
J. Pressure Vessel Technol (August,1995)
Related Chapters
Defect Assessment
Pipeline Integrity Assurance: A Practical Approach
Understanding the Problem
Design and Application of the Worm Gear
Basic Concepts
Design & Analysis of ASME Boiler and Pressure Vessel Components in the Creep Range