Predicted life of thick-wall P91 steel for cyclic high temperature service

Research output: Contribution to conferenceConference articleScientificpeer-review

Abstract

The ferritic-martensitic steel P91 (X10CrMoVNb9-1) is widely used in high temperature steam systems of power plants, and it is a candidate material for Gen-IV reactors. In comparison to austenitic steels, thick-wall P91 has relatively attractive mechanical and physical properties combined with resistance to stress corrosion cracking in water-steam environments. This study aimed to explore the combined cyclic, creep and relaxation behaviour of P91 material up to a component wall thickness of 60 mm. Uniaxial specimens were subjected to cyclic loadings with periodic forward creep or relaxation at peak stress. The results indicate that prior creep or intermediate relaxation periods up to 72 h will influence the subsequent cyclic softening of P91, but do not significantly reduce the cyclic life. In contrast, prior cycling has a detrimental effect on the subsequent creep life. A simplified creep-fatigue model is shown to predict life better than usual code-based approaches for cyclic service of P91 steel. Improved verification of all models would benefit from the availability of more extensive long-term data on P91 steel.
Original languageEnglish
Publication statusPublished - 2017
EventConference on Life/Crack Assessment & Failures in Industrial Structures, HIDA-7 - Portsmouth, United Kingdom
Duration: 15 May 201717 May 2017

Conference

ConferenceConference on Life/Crack Assessment & Failures in Industrial Structures, HIDA-7
Abbreviated titleHIDA-7
CountryUnited Kingdom
CityPortsmouth
Period15/05/1717/05/17

Fingerprint

Creep
Steel
Steam
Temperature
Martensitic steel
Austenitic steel
Ferritic steel
Stress corrosion cracking
Power plants
Physical properties
Availability
Fatigue of materials
Mechanical properties
Water

Keywords

  • P91 steel
  • creep-fatigue
  • cyclic behaviour
  • stress relaxation

Cite this

Pohja, R., Holmström, S., Auerkari, P., & Nurmela, A. (2017). Predicted life of thick-wall P91 steel for cyclic high temperature service. Paper presented at Conference on Life/Crack Assessment & Failures in Industrial Structures, HIDA-7, Portsmouth, United Kingdom.
Pohja, Rami ; Holmström, Stefan ; Auerkari, Pertti ; Nurmela, Asta. / Predicted life of thick-wall P91 steel for cyclic high temperature service. Paper presented at Conference on Life/Crack Assessment & Failures in Industrial Structures, HIDA-7, Portsmouth, United Kingdom.
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abstract = "The ferritic-martensitic steel P91 (X10CrMoVNb9-1) is widely used in high temperature steam systems of power plants, and it is a candidate material for Gen-IV reactors. In comparison to austenitic steels, thick-wall P91 has relatively attractive mechanical and physical properties combined with resistance to stress corrosion cracking in water-steam environments. This study aimed to explore the combined cyclic, creep and relaxation behaviour of P91 material up to a component wall thickness of 60 mm. Uniaxial specimens were subjected to cyclic loadings with periodic forward creep or relaxation at peak stress. The results indicate that prior creep or intermediate relaxation periods up to 72 h will influence the subsequent cyclic softening of P91, but do not significantly reduce the cyclic life. In contrast, prior cycling has a detrimental effect on the subsequent creep life. A simplified creep-fatigue model is shown to predict life better than usual code-based approaches for cyclic service of P91 steel. Improved verification of all models would benefit from the availability of more extensive long-term data on P91 steel.",
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Pohja, R, Holmström, S, Auerkari, P & Nurmela, A 2017, 'Predicted life of thick-wall P91 steel for cyclic high temperature service' Paper presented at Conference on Life/Crack Assessment & Failures in Industrial Structures, HIDA-7, Portsmouth, United Kingdom, 15/05/17 - 17/05/17, .

Predicted life of thick-wall P91 steel for cyclic high temperature service. / Pohja, Rami; Holmström, Stefan; Auerkari, Pertti; Nurmela, Asta.

2017. Paper presented at Conference on Life/Crack Assessment & Failures in Industrial Structures, HIDA-7, Portsmouth, United Kingdom.

Research output: Contribution to conferenceConference articleScientificpeer-review

TY - CONF

T1 - Predicted life of thick-wall P91 steel for cyclic high temperature service

AU - Pohja, Rami

AU - Holmström, Stefan

AU - Auerkari, Pertti

AU - Nurmela, Asta

N1 - MIP: Safe and Sustainable

PY - 2017

Y1 - 2017

N2 - The ferritic-martensitic steel P91 (X10CrMoVNb9-1) is widely used in high temperature steam systems of power plants, and it is a candidate material for Gen-IV reactors. In comparison to austenitic steels, thick-wall P91 has relatively attractive mechanical and physical properties combined with resistance to stress corrosion cracking in water-steam environments. This study aimed to explore the combined cyclic, creep and relaxation behaviour of P91 material up to a component wall thickness of 60 mm. Uniaxial specimens were subjected to cyclic loadings with periodic forward creep or relaxation at peak stress. The results indicate that prior creep or intermediate relaxation periods up to 72 h will influence the subsequent cyclic softening of P91, but do not significantly reduce the cyclic life. In contrast, prior cycling has a detrimental effect on the subsequent creep life. A simplified creep-fatigue model is shown to predict life better than usual code-based approaches for cyclic service of P91 steel. Improved verification of all models would benefit from the availability of more extensive long-term data on P91 steel.

AB - The ferritic-martensitic steel P91 (X10CrMoVNb9-1) is widely used in high temperature steam systems of power plants, and it is a candidate material for Gen-IV reactors. In comparison to austenitic steels, thick-wall P91 has relatively attractive mechanical and physical properties combined with resistance to stress corrosion cracking in water-steam environments. This study aimed to explore the combined cyclic, creep and relaxation behaviour of P91 material up to a component wall thickness of 60 mm. Uniaxial specimens were subjected to cyclic loadings with periodic forward creep or relaxation at peak stress. The results indicate that prior creep or intermediate relaxation periods up to 72 h will influence the subsequent cyclic softening of P91, but do not significantly reduce the cyclic life. In contrast, prior cycling has a detrimental effect on the subsequent creep life. A simplified creep-fatigue model is shown to predict life better than usual code-based approaches for cyclic service of P91 steel. Improved verification of all models would benefit from the availability of more extensive long-term data on P91 steel.

KW - P91 steel

KW - creep-fatigue

KW - cyclic behaviour

KW - stress relaxation

M3 - Conference article

ER -

Pohja R, Holmström S, Auerkari P, Nurmela A. Predicted life of thick-wall P91 steel for cyclic high temperature service. 2017. Paper presented at Conference on Life/Crack Assessment & Failures in Industrial Structures, HIDA-7, Portsmouth, United Kingdom.