Fatigue of stabilised steel in NPP primary piping - discussion on design curves

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

Abstract

The ASME Code Section III fatigue design methodology is based on local strain approach and transferability of material performance measured using small scale laboratory samples. Strain controlled tests data shall be transferred to fatigue assessment in a compatible way to provide relevant prediction and follow-up of fatigue usage. Transferability to real components is secured by appropriate margins and full scale testing. Transferability can be studied and improved through better simulation of component operation conditions such as loading mode and sequence, temperature and environment. But the design curves shall be based only on standard tests compatible with the design procedure. A new design curve for stainless steels has been adopted into the ASME Code Section III. However, it is suspected that derivation of the curve is not fully compatible with the design procedure. Variable temperature data has been mixed inappropriately. Furthermore, the code curve is not applicable to all grades of stainless steel. This paper reports contradictory data for stabilised austenitic stainless steels extending up to 10 million cycles. Niobium and titanium stabilised stainless steel specimens were sampled from 100% relevant material batches fabricated to be used in NPP primary piping. Fatigue tests periodically interrupted for holds indicated time and temperature dependent hardening during holds at 25°C to 325°C. Notable extension of fatigue life was measured when loading patterns consist of cyclic deformation in lower temperatures than hold annealing. Many NPP piping thermal transients separated by normal operation belong to this category and fatigue assessment based on standard fatigue data seems to underestimate fatigue endurance.
Original languageEnglish
Title of host publicationBaltica IX. International Conference on Life Management and Maintenance for Power Plants
EditorsPertti Auerkari, Juha Veivo
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Pages75-102
ISBN (Print)978-951-38-8025-5, 978-951-38-8026-2
Publication statusPublished - 2013
MoE publication typeA4 Article in a conference publication
EventBALTICA IX - International Conference on Life Management and Maintenance for Power Plants - Helsinki-Stockholm, Finland
Duration: 11 Jun 201313 Jun 2013

Publication series

SeriesVTT Technology
Number106
ISSN2242-1211

Conference

ConferenceBALTICA IX - International Conference on Life Management and Maintenance for Power Plants
CountryFinland
CityHelsinki-Stockholm
Period11/06/1313/06/13

Fingerprint

Fatigue of materials
Steel
Stainless steel
Temperature
Austenitic stainless steel
Niobium
Hardening
Durability
Titanium
Annealing
Testing

Cite this

Solin, J. (2013). Fatigue of stabilised steel in NPP primary piping - discussion on design curves. In P. Auerkari, & J. Veivo (Eds.), Baltica IX. International Conference on Life Management and Maintenance for Power Plants (pp. 75-102). Espoo: VTT Technical Research Centre of Finland. VTT Technology, No. 106
Solin, Jussi. / Fatigue of stabilised steel in NPP primary piping - discussion on design curves. Baltica IX. International Conference on Life Management and Maintenance for Power Plants. editor / Pertti Auerkari ; Juha Veivo. Espoo : VTT Technical Research Centre of Finland, 2013. pp. 75-102 (VTT Technology; No. 106).
@inproceedings{d8b12e3d841a43a28eddc71b01f415c5,
title = "Fatigue of stabilised steel in NPP primary piping - discussion on design curves",
abstract = "The ASME Code Section III fatigue design methodology is based on local strain approach and transferability of material performance measured using small scale laboratory samples. Strain controlled tests data shall be transferred to fatigue assessment in a compatible way to provide relevant prediction and follow-up of fatigue usage. Transferability to real components is secured by appropriate margins and full scale testing. Transferability can be studied and improved through better simulation of component operation conditions such as loading mode and sequence, temperature and environment. But the design curves shall be based only on standard tests compatible with the design procedure. A new design curve for stainless steels has been adopted into the ASME Code Section III. However, it is suspected that derivation of the curve is not fully compatible with the design procedure. Variable temperature data has been mixed inappropriately. Furthermore, the code curve is not applicable to all grades of stainless steel. This paper reports contradictory data for stabilised austenitic stainless steels extending up to 10 million cycles. Niobium and titanium stabilised stainless steel specimens were sampled from 100{\%} relevant material batches fabricated to be used in NPP primary piping. Fatigue tests periodically interrupted for holds indicated time and temperature dependent hardening during holds at 25°C to 325°C. Notable extension of fatigue life was measured when loading patterns consist of cyclic deformation in lower temperatures than hold annealing. Many NPP piping thermal transients separated by normal operation belong to this category and fatigue assessment based on standard fatigue data seems to underestimate fatigue endurance.",
author = "Jussi Solin",
year = "2013",
language = "English",
isbn = "978-951-38-8025-5",
series = "VTT Technology",
publisher = "VTT Technical Research Centre of Finland",
number = "106",
pages = "75--102",
editor = "Pertti Auerkari and Juha Veivo",
booktitle = "Baltica IX. International Conference on Life Management and Maintenance for Power Plants",
address = "Finland",

}

Solin, J 2013, Fatigue of stabilised steel in NPP primary piping - discussion on design curves. in P Auerkari & J Veivo (eds), Baltica IX. International Conference on Life Management and Maintenance for Power Plants. VTT Technical Research Centre of Finland, Espoo, VTT Technology, no. 106, pp. 75-102, BALTICA IX - International Conference on Life Management and Maintenance for Power Plants, Helsinki-Stockholm, Finland, 11/06/13.

Fatigue of stabilised steel in NPP primary piping - discussion on design curves. / Solin, Jussi.

Baltica IX. International Conference on Life Management and Maintenance for Power Plants. ed. / Pertti Auerkari; Juha Veivo. Espoo : VTT Technical Research Centre of Finland, 2013. p. 75-102 (VTT Technology; No. 106).

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

TY - GEN

T1 - Fatigue of stabilised steel in NPP primary piping - discussion on design curves

AU - Solin, Jussi

PY - 2013

Y1 - 2013

N2 - The ASME Code Section III fatigue design methodology is based on local strain approach and transferability of material performance measured using small scale laboratory samples. Strain controlled tests data shall be transferred to fatigue assessment in a compatible way to provide relevant prediction and follow-up of fatigue usage. Transferability to real components is secured by appropriate margins and full scale testing. Transferability can be studied and improved through better simulation of component operation conditions such as loading mode and sequence, temperature and environment. But the design curves shall be based only on standard tests compatible with the design procedure. A new design curve for stainless steels has been adopted into the ASME Code Section III. However, it is suspected that derivation of the curve is not fully compatible with the design procedure. Variable temperature data has been mixed inappropriately. Furthermore, the code curve is not applicable to all grades of stainless steel. This paper reports contradictory data for stabilised austenitic stainless steels extending up to 10 million cycles. Niobium and titanium stabilised stainless steel specimens were sampled from 100% relevant material batches fabricated to be used in NPP primary piping. Fatigue tests periodically interrupted for holds indicated time and temperature dependent hardening during holds at 25°C to 325°C. Notable extension of fatigue life was measured when loading patterns consist of cyclic deformation in lower temperatures than hold annealing. Many NPP piping thermal transients separated by normal operation belong to this category and fatigue assessment based on standard fatigue data seems to underestimate fatigue endurance.

AB - The ASME Code Section III fatigue design methodology is based on local strain approach and transferability of material performance measured using small scale laboratory samples. Strain controlled tests data shall be transferred to fatigue assessment in a compatible way to provide relevant prediction and follow-up of fatigue usage. Transferability to real components is secured by appropriate margins and full scale testing. Transferability can be studied and improved through better simulation of component operation conditions such as loading mode and sequence, temperature and environment. But the design curves shall be based only on standard tests compatible with the design procedure. A new design curve for stainless steels has been adopted into the ASME Code Section III. However, it is suspected that derivation of the curve is not fully compatible with the design procedure. Variable temperature data has been mixed inappropriately. Furthermore, the code curve is not applicable to all grades of stainless steel. This paper reports contradictory data for stabilised austenitic stainless steels extending up to 10 million cycles. Niobium and titanium stabilised stainless steel specimens were sampled from 100% relevant material batches fabricated to be used in NPP primary piping. Fatigue tests periodically interrupted for holds indicated time and temperature dependent hardening during holds at 25°C to 325°C. Notable extension of fatigue life was measured when loading patterns consist of cyclic deformation in lower temperatures than hold annealing. Many NPP piping thermal transients separated by normal operation belong to this category and fatigue assessment based on standard fatigue data seems to underestimate fatigue endurance.

M3 - Conference article in proceedings

SN - 978-951-38-8025-5

SN - 978-951-38-8026-2

T3 - VTT Technology

SP - 75

EP - 102

BT - Baltica IX. International Conference on Life Management and Maintenance for Power Plants

A2 - Auerkari, Pertti

A2 - Veivo, Juha

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Solin J. Fatigue of stabilised steel in NPP primary piping - discussion on design curves. In Auerkari P, Veivo J, editors, Baltica IX. International Conference on Life Management and Maintenance for Power Plants. Espoo: VTT Technical Research Centre of Finland. 2013. p. 75-102. (VTT Technology; No. 106).