Creep damage and long term life of steam line components

Case X20

Stefan Holmström, Pertti Auerkari, Jorma Salonen, Anssi Laukkanen, Juhani Rantala, Reino Nikkarila, Jarmo Junttanen

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

Abstract

Hot steam lines operate at high temperatures and are designed against creep. In service they will consume the creep life at the highest rate in locations with the most adverse combination of material strength (weakness) and high stress (e.g. system loads). Adverse effects in stress state are promoted by features of geometry and discontinuities in the materials properties. In practice it is essential to find the areas of maximum damage, as these will determine the locations and timing to inspect and finally to repair or replace before failures or unplanned outages. The inspection experience from power plant steam systems have provided the established views on the expected locations of the early creep damage, and rules on timing the next inspection. The experience has also shown that optimal timing is materials dependent, and that the steel grade X20CrMoV11-1 (X20, 11% Cr steel) performs particularly well in the inspection statistics. This paper describes a case with observed creep cavitation and cracking in a branch weld of a X20 steam header that was replaced after 135 000 service hours. The characteristics of the observed damage and its evolution are discussed.
Original languageEnglish
Title of host publicationBaltica VIII
Subtitle of host publicationLife Management and Maintenance for Power Plants
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Pages154-166
Volume2
ISBN (Electronic)978-951-38-7594-7
ISBN (Print)978-951-38-7593-2
Publication statusPublished - 2010
MoE publication typeB3 Non-refereed article in conference proceedings
EventBALTICA VIII - International Conference on Life Management and Maintenance for Power Plants - Helsinki-Stockholm, Finland
Duration: 18 May 201020 May 2010

Publication series

NameVTT Symposium
PublisherVTT
Number265
ISSN (Print)0357–9387
ISSN (Electronic)1455–0873

Conference

ConferenceBALTICA VIII - International Conference on Life Management and Maintenance for Power Plants
CountryFinland
CityHelsinki-Stockholm
Period18/05/1020/05/10

Fingerprint

Steam piping systems
Creep
Inspection
Steam power plants
Steel
Cavitation
Outages
Strength of materials
Loads (forces)
Materials properties
Welds
Repair
Steam
Statistics
Geometry
Temperature

Cite this

Holmström, S., Auerkari, P., Salonen, J., Laukkanen, A., Rantala, J., Nikkarila, R., & Junttanen, J. (2010). Creep damage and long term life of steam line components: Case X20. In Baltica VIII: Life Management and Maintenance for Power Plants (Vol. 2, pp. 154-166). Espoo: VTT Technical Research Centre of Finland. VTT Symposium, No. 265
Holmström, Stefan ; Auerkari, Pertti ; Salonen, Jorma ; Laukkanen, Anssi ; Rantala, Juhani ; Nikkarila, Reino ; Junttanen, Jarmo. / Creep damage and long term life of steam line components : Case X20. Baltica VIII: Life Management and Maintenance for Power Plants. Vol. 2 Espoo : VTT Technical Research Centre of Finland, 2010. pp. 154-166 (VTT Symposium; No. 265).
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abstract = "Hot steam lines operate at high temperatures and are designed against creep. In service they will consume the creep life at the highest rate in locations with the most adverse combination of material strength (weakness) and high stress (e.g. system loads). Adverse effects in stress state are promoted by features of geometry and discontinuities in the materials properties. In practice it is essential to find the areas of maximum damage, as these will determine the locations and timing to inspect and finally to repair or replace before failures or unplanned outages. The inspection experience from power plant steam systems have provided the established views on the expected locations of the early creep damage, and rules on timing the next inspection. The experience has also shown that optimal timing is materials dependent, and that the steel grade X20CrMoV11-1 (X20, 11{\%} Cr steel) performs particularly well in the inspection statistics. This paper describes a case with observed creep cavitation and cracking in a branch weld of a X20 steam header that was replaced after 135 000 service hours. The characteristics of the observed damage and its evolution are discussed.",
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Holmström, S, Auerkari, P, Salonen, J, Laukkanen, A, Rantala, J, Nikkarila, R & Junttanen, J 2010, Creep damage and long term life of steam line components: Case X20. in Baltica VIII: Life Management and Maintenance for Power Plants. vol. 2, VTT Technical Research Centre of Finland, Espoo, VTT Symposium, no. 265, pp. 154-166, BALTICA VIII - International Conference on Life Management and Maintenance for Power Plants, Helsinki-Stockholm, Finland, 18/05/10.

Creep damage and long term life of steam line components : Case X20. / Holmström, Stefan; Auerkari, Pertti; Salonen, Jorma; Laukkanen, Anssi; Rantala, Juhani; Nikkarila, Reino; Junttanen, Jarmo.

Baltica VIII: Life Management and Maintenance for Power Plants. Vol. 2 Espoo : VTT Technical Research Centre of Finland, 2010. p. 154-166 (VTT Symposium; No. 265).

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

TY - GEN

T1 - Creep damage and long term life of steam line components

T2 - Case X20

AU - Holmström, Stefan

AU - Auerkari, Pertti

AU - Salonen, Jorma

AU - Laukkanen, Anssi

AU - Rantala, Juhani

AU - Nikkarila, Reino

AU - Junttanen, Jarmo

PY - 2010

Y1 - 2010

N2 - Hot steam lines operate at high temperatures and are designed against creep. In service they will consume the creep life at the highest rate in locations with the most adverse combination of material strength (weakness) and high stress (e.g. system loads). Adverse effects in stress state are promoted by features of geometry and discontinuities in the materials properties. In practice it is essential to find the areas of maximum damage, as these will determine the locations and timing to inspect and finally to repair or replace before failures or unplanned outages. The inspection experience from power plant steam systems have provided the established views on the expected locations of the early creep damage, and rules on timing the next inspection. The experience has also shown that optimal timing is materials dependent, and that the steel grade X20CrMoV11-1 (X20, 11% Cr steel) performs particularly well in the inspection statistics. This paper describes a case with observed creep cavitation and cracking in a branch weld of a X20 steam header that was replaced after 135 000 service hours. The characteristics of the observed damage and its evolution are discussed.

AB - Hot steam lines operate at high temperatures and are designed against creep. In service they will consume the creep life at the highest rate in locations with the most adverse combination of material strength (weakness) and high stress (e.g. system loads). Adverse effects in stress state are promoted by features of geometry and discontinuities in the materials properties. In practice it is essential to find the areas of maximum damage, as these will determine the locations and timing to inspect and finally to repair or replace before failures or unplanned outages. The inspection experience from power plant steam systems have provided the established views on the expected locations of the early creep damage, and rules on timing the next inspection. The experience has also shown that optimal timing is materials dependent, and that the steel grade X20CrMoV11-1 (X20, 11% Cr steel) performs particularly well in the inspection statistics. This paper describes a case with observed creep cavitation and cracking in a branch weld of a X20 steam header that was replaced after 135 000 service hours. The characteristics of the observed damage and its evolution are discussed.

M3 - Conference article in proceedings

SN - 978-951-38-7593-2

VL - 2

T3 - VTT Symposium

SP - 154

EP - 166

BT - Baltica VIII

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Holmström S, Auerkari P, Salonen J, Laukkanen A, Rantala J, Nikkarila R et al. Creep damage and long term life of steam line components: Case X20. In Baltica VIII: Life Management and Maintenance for Power Plants. Vol. 2. Espoo: VTT Technical Research Centre of Finland. 2010. p. 154-166. (VTT Symposium; No. 265).