Abstract
As the Boiler and Pressure Vessel Code continues to gain popularity worldwide, it is not uncommon that many users are mystified by the 1.1 factor used to establish the ultimate tensile strength above room temperature in developing the related design stresses of Section II Part D Stress Tables. Questions often arise about the origin and purpose of the factor, the reason for it not being applied to the yield strength, its due considerations regarding the tested tensile strength value of an alloy batch when accepting the batch for construction use, and more. Not having historic background or reliable sources for explicit explanations, some users tend to misinterpret the factor, abuse its application, incorrectly define alloy acceptance or qualification criteria, and mistakenly manipulate the safety margin in component design. To help the Code users who struggle with these frequent and confusing issues, particularly those in the nuclear industry where rigorous criteria are required for component design and alloy acceptance or qualification, this paper is intended to demystify the 1.1 factor and facilitate knowledgeable interpretation and use of the Section II Part D Stress Tables as well as relevant Mandatory Appendices. A brief review is first given on the background of the 1.1 factor, followed by a summary of its application in the Stress Tables. The provenance and purpose of the factor are then discussed in detail with graphic examples. Finally, current applicability and necessity of the factor are considered through a demonstration using example alloys.
| Original language | English |
|---|---|
| Title of host publication | Codes and Standards |
| Publisher | American Society of Mechanical Engineers (ASME) |
| ISBN (Electronic) | 9780791886144 |
| DOIs | |
| State | Published - 2022 |
| Event | ASME 2022 Pressure Vessels and Piping Conference, PVP 2022 - Las Vegas, United States Duration: Jul 17 2022 → Jul 22 2022 |
Publication series
| Name | American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP |
|---|---|
| Volume | 1 |
| ISSN (Print) | 0277-027X |
Conference
| Conference | ASME 2022 Pressure Vessels and Piping Conference, PVP 2022 |
|---|---|
| Country/Territory | United States |
| City | Las Vegas |
| Period | 07/17/22 → 07/22/22 |
Funding
The author would like to thank John Grubb, Mike Gold, and Blaine Roberts for providing invaluable historical accounts about the origin of the 1.1 factor at his request for perpetual documentation of its technical rationale in the ASME Materials Properties Database. Thanks also go to Bob Swindeman and Jude Foulds for helping the author in his initial efforts to seek historical records and track down potential sources, and particularly for Jude Foulds’ extensive discussion and erudite insights into the Code during his review of this paper. This paper is presented to the 2022 PVP Conference in memory of Mike Gold. This work is sponsored by the U.S. Department of Energy, Office of Nuclear Energy Science and Technology under contract DE-AC05-00OR22725 with Oak Ridge National Laboratory, managed by UT-Battelle, LLC. This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains, and by accepting the article for publication, the publisher acknowledges that the United States Government retains, a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for United States Government purposes. This work is sponsored by the U.S. Department of Energy, Office of Nuclear Energy Science and Technology under contract DE-AC05-00OR22725 with Oak Ridge National Laboratory, managed by UT-Battelle, LLC.
Keywords
- 1.1 factor
- trend curve
- ultimate tensile strength